Analogs of green tea polyphenols as chemotherapeutic and chemopreventive agents

ABSTRACT

Novel compounds useful as chemotherapeutic and chemopreventive agents are provided. The compounds are analogs of polyphenol catechins that occur in green tea, such as epigallocatichin-3-gallate (EGCG), and have the structure of formula (I) 
                         
wherein R 1  through R 11  are defined herein. Preferred R 4  moieties are selected from O, S, NH and CH 2 , and in exemplary compounds, R 4  is O and R 5  is a tri-substituted aroyloxy substituent, such as a 3,4,5-substituted benzoyloxy group. Pharmaceutical compositions are provided as well, as are methods of chemotherapy and chemoprevention.

TECHNICAL FIELD

This invention relates generally to analogs of polyphenol catechins thatoccur in green tea. More particularly, the invention pertains to novelanalogs of the catechin, (−)-epigallocatechin-3-gallate (EGCG), and totheir use as chemotherapeutic and chemopreventive agents.

BACKGROUND

Cancer is the second leading cause of death in the United States,exceeded only by heart disease. Current pharmacological treatments forcancer utilize a toxic dose of a compound that is administered in aprecise dosing range to preferentially destroy the cancerous cells(chemotherapy), and minimize damage to healthy tissue. Despite effortsto focus the toxic effects on the cancerous tissues, severe or evenlife-threatening adverse effects may occur, such as serious disorders ofthe blood, gastrointestinal tract, liver, kidneys, and other organs.Most current anticancer drugs thus have a narrow therapeutic window: therange between the therapeutic dose and the maximum tolerated dose isvery small. Due to this toxicity, as well as the fact that mostanticancer drugs are administered intravenously, nearly all cancerchemotherapy must be administered in a hospital or clinic. An additionalproblem with most current cancer chemotherapy is that cancers frequentlydevelop resistance to the drugs, so that recurrence of disease iscommon.

It is a goal of cancer researchers to discover efficacious anticanceragents while avoiding the adverse effects of chemotherapy treatments.Epidemiology offers some clues in this regard, and has led to thediscovery of safe anticancer agents. By examining the practices ofcultures exhibiting a lower incidence of cancer and investigating thepossible sources of the decreased incidence of disease, researchers maybe able to discover that the food or drink consumed by the people ofthat culture contains compounds that have anticancer properties. Thesedietary compounds possessing anticancer properties can then be modifiedto enhance their anticancer effects while retaining their safety. Ofparticular interest in this regard are certain polyphenols that occur ingreen tea.

Specifically, compounds such as the catechins,(−)-epigallocatechin-3-gallate (EGCG), (−)-epigallocatechin (EGC),(−)-epicatechin-3-gallate (ECG), and (−)-epicatechin (EC) have beenimplicated in cancer chemoprevention. Both EGCG and EGC exhibitsubstantial anticancer activity (EGCG is particularly potent), with ECGand EC somewhat less active.

Researchers studying these naturally occurring polyphenols havedetermined that EGCG is not only the most abundant of the abovecatechins, but also the most potent chemopreventive component in greentea. A large number of in vitro and in vivo studies have shown EGCG topossess a wide variety of anticancer activities. In animal studies,orally administered EGCG and related green tea polyphenols have shownefficacy in preventing and treating cancers of the lung, breast, liver,skin, esophagus, stomach, duodenum, pancreas, and colon (Hirosi et al.(1997) Cancer Lett. 112:141–147). As an antioxidant, EGCG exertsantimutagenic and chemoprotective effects through neutralization of freeradicals, protection of DNA from strand breaks and other damage causedby reactive oxygen species (Anderson et al. (2001) Carcinogenesis22:1189–1193), and inhibition of oxidation of some carcinogenicsubstrates of human cytochrome P450 (Muto et al. (2001) Mutat. Res.479:197–202). In general, EGCG inhibits the metabolic activation ofprocarcinogens by cytochrome P450, which represents a significantchemoprotective activity against carcinogenesis (ibid).

Another proposed anticancer activity of EGCG involves the induction ofapoptosis. One mechanism of apoptosis appears to be binding of EGCG toFas on the cell surface, which triggers Fas-mediated apoptosis (Hayakawaet al. (2001) Biochem. Biophys. Res. Commun. 285:1102–1106). Otherresearchers have suggested that normal cells are not affected by theapoptotic effects of green tea polyphenols because EGCG and otherconstituents of green tea cause the induction of p57, which acts toinhibit apoptosis in untransformed cells (Hsu et al. (2001) AnticancerRes. 21(6A):3743–3748).

Other anticancer mechanisms include, without limitation: inhibition oftopoisomerases I and II (Suzuki et al. (2001) Biol. Pharm. Bull.24:1088–1090); inhibition of nuclear factor kappa-B (NFκB), possiblythrough inhibition of the IκB kinase complex (Yang et al. (2001) Mol.Pharmacol. 60:528–533), which results in the suppression of NO synthesisand subsequent generation of carcinogenic nitrites; scavenging ofcarcinogenic nitrites (Pannala et al. (1997) Biochem. Biophys. Res.Commun. 232:164–168); inhibition of matrix metalloproteinases involvedin tumor metastasis (Isemura et al. (2000) Biofactors 13:81–85; Demeuleet al. (2000), Biochim. Biophys. Acta 1478:51–60); inhibition of theandrogen receptor in prostate cancer (Ren et al. (2000) Oncogene19:1924–1932); inhibition of cellular hyperproliferation induced byoverexpression of epidermal growth factor receptor (Liang et al. (1997)J. Cell Biochem. 67:55–65); and inhibition of angiogenesis, at least inpart by suppressing the induction of vascular endothelial growth factor(VEGF) (Jung et al. (2001) Br. J. Cancer 84:844–850).

EGCG can be obtained as the natural product (see, e.g., U.S. Pat. No.6,210,679 to Bailey et al.) or chemically synthesized using anenantioselective synthesis recently developed at SRI International(Menlo Park, Calif.); see Zaveri (2001) Organic Letters 3(6):843–846.However, EGCG per se is not a viable candidate for use as a therapeuticagent because it is only minimally bioavailable when administeredorally, and in addition, EGCG is extensively conjugated by action of theliver. Because of the poor absorption when given orally, one would haveto drink at least 8–10 cups of green tea a day to gain itschemopreventive benefit (EGCG is present in green tea at a concentrationof about 200 mg per brewed cup; see Mukhtar et al. (1999) Toxicol. Sci.52 (suppl.):111–117). Furthermore, green tea contains 70 mg of caffeineper cup, so drinking enough for chemoprevention would result incaffeine-related side effects. These are being observed in the ongoingclinical trials of green tea.

Several researchers have attempted to synthesize analogs of EGCG thatovercome the aforementioned limitations inherent in EGCG itself. Forexample, it is not yet known which of the enantiomers of EGCG isresponsible for the anticancer activity of this compound. Anenantioselective synthesis of EGCG was devised involving synthesizingthe three aromatic fragments separately, and then assembling them in astereoselective fashion (Li and Chan (2001) Organic Letters3(5):739–741). These authors however did not report any resultsregarding the relative efficacy of either enantiomer. Zaveri (2001),supra, describes synthesis of a 3,4,5-trimethoxybenzoyl ester analogueof EGCG and the 2α,3β enantiomer thereof. Although both compoundsdescribed by Zaveri were found to inhibit the growth of breast cancercell lines in vitro, the potency of these compounds was somewhat lessthan that of EGCG itself.

Accordingly, there is a need for synthetic strategies for generatinganalogs of EGCG and other green tea polyphenols, in order to optimizethe chemopreventive and chemotherapeutic effects of these compounds. Thepresent invention is the result of extensive, systematic research todesign novel flavanoids related to EGCG, but optimized to enhance theiranticancer activity and retain a low toxicity.

SUMMARY OF THE INVENTION

The present invention is directed to novel EGCG analogs that, like EGCGper se, are highly effective anti-cancer agents, but which in contrastto EGCG possess excellent oral bioavailability. The novel compoundsprovide a number of advantages relative to compounds that are known orcurrently under consideration as anticancer agents. For example, thepresent compounds have a very broad therapeutic window, in turn meaningthat no toxicity will be seen even at high doses. In addition, thecompounds do not give rise to the numerous and debilitating side effectsthat are associated with many drugs. From a safety standpoint, then, thenovel compounds are optimal. Furthermore, the present compounds havesimple molecular structures, and may be readily synthesized usingstraightforward synthetic techniques. Pharmaceutical compositionsformulated with the novel compounds are stable and readily delivered,providing excellent bioavailability.

The invention thus provides novel compounds that are useful aschemotherapeutic and chemopreventive agents. The novel compounds areflavanoids that are structurally related to EGCG and other polyphenolsfound in green tea.

In one embodiment, a therapeutic compound is provided having thestructure (I)

wherein:

R¹, R², and R³ are independently selected from the group consisting ofhydroxyl, halo, sulfhydryl, alkoxy, aryloxy, and aralkyloxy, and furtherwherein either R¹ and R² or R² and R³ can be linked to form a cyclicgroup;

R⁴ is selected from O, S, NR^(x), and CR^(y)R^(z), wherein R^(x), R^(y),and R^(z) are hydrogen or alkyl;

R⁵ is selected from the group consisting of hydroxyl, acyloxy (includingaroyloxy), sulfhydryl, and N(R^(x)) wherein the R^(x) may be the same ordifferent and are as defined previously;

R⁶, R⁷, R⁸, and R⁹ are independently selected from the group consistingof hydrogen, alkyl, alkoxy, aryloxy, and aralkyloxy, providing thateither R⁶ and R⁷, or R⁸ and R⁹, may be linked together to form a cyclicstructure selected from five-membered rings, six-membered rings, andfused five-membered and/or six-membered rings, wherein the cyclicstructure is aromatic, alicyclic, heteroaromatic, or heteroalicyclic,and has zero to 4 non-hydrogen substituents and zero to 3 heteroatoms;and

R¹⁰ and R¹¹ are independently selected from the group consisting ofhydrogen, hydroxyl, alkyl, alkoxy, and halo,

with the proviso that when (a) R⁷, R⁹, R¹⁰, and R¹¹ are hydrogen, (b)R¹, R², R³, R⁶, and R⁸ are hydroxyl, and (c) R⁴ is O, then (d) R⁵ isother than 3,4,5-trihydroxybenzoyloxy or 3,4,5-trimethoxybenzoyloxy.

In a further embodiment, methods are provided for synthesizing thecompounds of the invention. The methods are straightforward, avoid theuse of extreme reaction conditions and toxic solvents, and provide thedesired products in high yield.

In another embodiment, the invention encompasses pharmaceuticalcompositions containing a novel compound as provided herein incombination with a pharmaceutically acceptable carrier. Preferably,although not necessarily, such compositions are oral dosage forms andthus contain a carrier suitable for oral drug administration.

In an additional embodiment, the invention is directed to a method fortreating an individual suffering from cancer, comprising administeringto the individual a therapeutically effective amount of a novel compoundas provided herein. In addition to their general utility aschemotherapeutic agents, the compounds are also useful inchemoprevention. Therefore, the invention additionally pertains to amethod for preventing cancer, by administering a therapeuticallyeffective amount of a compound of the invention to a patient. Generally,in chemoprevention, the patient will have been identified as being at anelevated risk of developing cancer. Such patients include, for example,those with a family history of cancer or a particular type of cancer, aswell as those who have undergone genetic analysis and thereby determinedto be genitically predisposed to develop cancer or a particular type ofcancer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates the stepwise synthesis of threecompounds of the invention, SR 13194, SR 13195, and SR 13196, asdescribed in Examples 1 through 3, respectively.

FIG. 2 schematically illustrates the stepwise synthesis of an additionalcompound of the invention, SR 13197, as described in Example 4.

FIG. 3 schematically illustrates the stepwise synthesis of threeadditional compounds of the invention, SR 13198, SR 13199, and SR 13200,as described in Examples 5 through 7, respectively.

FIG. 4 schematically illustrates the stepwise synthesis of threeadditional compounds of the invention, SR 13911, SR 13912, and SR 13913,as described in Examples 8 through 10, respectively.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

I. Definitions and Nomenclature:

Unless otherwise indicated, the invention is not limited to specificsynthetic methods, analogs, substituents, pharmaceutical formulations,formulation components, modes of administration, or the like, as suchmay vary. It is also to be understood that the terminology used hereinis for the purpose of describing particular embodiments only and is notintended to be limiting.

As used in the specification and the appended claims, the singular forms“a,” “an,” and “the” include plural referents unless the context clearlydictates otherwise. Thus, for example, reference to “a substituent”includes a single substituent as well as two or more substituents thatmay be the same or different, reference to “a compound” encompasses acombination or mixture of different compounds as well as a singlecompound, reference to “a pharmaceutically acceptable carrier” includestwo or more such carriers as well as a single carrier, and the like.

In this specification and in the claims that follow, reference will bemade to a number of terms, which shall be defined to have the followingmeanings:

In this specification and in the claims that follow, reference will bemade to a number of terms, which shall be defined to have the followingmeanings:

As used herein, the phrase “having the formula” or “having thestructure” is not intended to be limiting and is used in the same waythat the term “comprising” is commonly used.

The term “alkyl” as used herein refers to a branched or unbranchedsaturated hydrocarbon group typically although not necessarilycontaining 1 to about 24 carbon atoms, such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, t-butyl, octyl, decyl, and the like, aswell as cycloalkyl groups such as cyclopentyl, cyclohexyl, and the like.Generally, although again not necessarily, alkyl groups herein contain 1to about 18 carbon atoms, preferably 1 to about 12 carbon atoms. Theterm “lower alkyl” intends an alkyl group of 1 to 6 carbon atoms.Preferred substituents identified as “C₁–C₆ alkyl” or “lower alkyl”contain 1 to 3 carbon atoms, and particularly preferred suchsubstituents contain 1 or 2 carbon atoms (i.e., methyl and ethyl).“Substituted alkyl” refers to alkyl substituted with one or moresubstituent groups, and the terms “heteroatom-containing alkyl” and“heteroalkyl” refer to alkyl in which at least one carbon atom isreplaced with a heteroatom, as described in further detail infra. If nototherwise indicated, the terms “alkyl” and “lower alkyl” include linear,branched, cyclic, unsubstituted, substituted, and/orheteroatom-containing alkyl or lower alkyl, respectively.

The term “alkenyl” as used herein refers to a linear, branched or cyclichydrocarbon group of 2 to about 24 carbon atoms containing at least onedouble bond, such as ethenyl, n-propenyl, isopropenyl, n-butenyl,isobutenyl, octenyl, decenyl, tetradecenyl, hexadecenyl, eicosenyl,tetracosenyl, and the like. Generally, although again not necessarily,alkenyl groups herein contain 2 to about 18 carbon atoms, preferably 2to 12 carbon atoms. The term “lower alkenyl” intends an alkenyl group of2 to 6 carbon atoms, and the specific term “cycloalkenyl” intends acyclic alkenyl group, preferably having 5 to 8 carbon atoms. The term“substituted alkenyl” refers to alkenyl substituted with one or moresubstituent groups, and the terms “heteroatom-containing alkenyl” and“heteroalkenyl” refer to alkenyl in which at least one carbon atom isreplaced with a heteroatom. If not otherwise indicated, the terms“alkenyl” and “lower alkenyl” include linear, branched, cyclic,unsubstituted, substituted, and/or heteroatom-containing alkenyl andlower alkenyl, respectively.

The term “alkynyl” as used herein refers to a linear or branchedhydrocarbon group of 2 to 24 carbon atoms containing at least one triplebond, such as ethynyl, n-propynyl, and the like. Generally, althoughagain not necessarily, alkynyl groups herein contain 2 to about 18carbon atoms, preferably 2 to 12 carbon atoms. The term “lower alkynyl”intends an alkynyl group of 2 to 6 carbon atoms. The term “substitutedalkynyl” refers to alkynyl substituted with one or more substituentgroups, and the terms “heteroatom-containing alkynyl” and“heteroalkynyl” refer to alkynyl in which at least one carbon atom isreplaced with a heteroatom. If not otherwise indicated, the terms“alkynyl” and “lower alkynyl” include linear, branched, unsubstituted,substituted, and/or heteroatom-containing alkynyl and lower alkynyl,respectively.

The term “alkoxy” as used herein intends an alkyl group bound through asingle, terminal ether linkage; that is, an “alkoxy” group may berepresented as —O-alkyl where alkyl is as defined above. A “loweralkoxy” group intends an alkoxy group containing 1 to 6 carbon atoms,and includes, for example, methoxy, ethoxy, n-propoxy, isopropoxy,t-butyloxy, etc. Preferred substituents identified as “C₁–C₆ alkoxy” or“lower alkoxy” herein contain 1 to 3 carbon atoms, and particularlypreferred such substituents contain 1 or 2 carbon atoms (i.e., methoxyand ethoxy).

The term “aryl” as used herein, and unless otherwise specified, refersto an aromatic substituent containing a single aromatic ring or multiplearomatic rings that are fused together, directly linked, or indirectlylinked (such that the different aromatic rings are bound to a commongroup such as a methylene or ethylene moiety). Preferred aryl groupscontain 5 to 20 carbon atoms, and particularly preferred aryl groupscontain 5 to 14 carbon atoms. Exemplary aryl groups contain one aromaticring or two fused or linked aromatic rings, e.g., phenyl, naphthyl,biphenyl, diphenylether, diphenylamine, benzophenone, and the like.“Substituted aryl” refers to an aryl moiety substituted with one or moresubstituent groups, and the terms “heteroatom-containing aryl” and“heteroaryl” refer to aryl substituent, in which at least one carbonatom is replaced with a heteroatom, as will be described in furtherdetail infra. If not otherwise indicated, the term “aryl” includesunsubstituted, substituted, and/or heteroatom-containing aromaticsubstituents.

The term “aryloxy” as used herein refers to an aryl group bound througha single, terminal ether linkage, wherein “aryl” is as defined above. An“aryloxy” group may be represented as —O-aryl where aryl is as definedabove. Preferred aryloxy groups contain 5 to 20 carbon atoms, andparticularly preferred aryloxy groups contain 5 to 14 carbon atoms.Examples of aryloxy groups include, without limitation, phenoxy,o-halo-phenoxy, m-halo-phenoxy, p-halo-phenoxy, o-methoxy-phenoxy,m-methoxy-phenoxy, p-methoxy-phenoxy, 2,4-dimethoxy-phenoxy,3,4,5-trimethoxy-phenoxy, and the like.

The term “aroyl” (e.g., benzoyl) refers to a substituent having thestructure —(CO)-aryl (e.g., —(CO)-phenyl), and the term “aroyloxy”(e.g., benzoyloxy) refers to a substituent having the structure—O—(CO)-aryl (e.g., —O—(CO)-phenyl).

The term “aralkyl” refers to an alkyl group with an aryl substituent,wherein “aryl” and “alkyl” are as defined above. Preferred aralkylgroups contain 5 to 20 carbon atoms, and particularly preferred aralkylgroups contain 5 to 12 carbon atoms. Examples of aralkyl groups include,without limitation, benzyl, 2-phenyl-ethyl, 3-phenyl-propyl,4-phenyl-butyl, 5-phenyl-pentyl, 4-phenylcyclohexyl, 4-benzylcyclohexyl,4-phenylcyclohexylmethyl, 4-benzylcyclohexylmethyl, and the like.

The term “aralkyloxy” refers to an aralkyl group bound through a single,terminal ether linkage. As above, an “aralkyloxy” group may berepresented as —O-Alk(Ar) wherein “Alk” is an alkyl group and “Ar” is anaryl substituent. Preferred aralkyloxy groups contain 5 to 20 carbonatoms, and particularly preferred aralkyloxy groups contain 5 to 12carbon atoms. Aralkyloxy substituents include, for example, benzyloxy,2-phenoxy-ethyl, 3-phenoxy-propyl, 2-phenoxy-propyl,2-methyl-3-phenoxypropyl, 2-ethyl-3-phenoxypropyl, 4-phenoxy-butyl,3-phenoxy-butyl, 2-methyl-4-phenoxybutyl, 4-phenoxycyclohexyl,4-benzyloxycyclohexyl, 4-phenoxy-cyclohexylmethyl,2-(4-phenoxy-cyclohexyl)-ethyl, and the like.

The term “cyclic” refers to alicyclic or aromatic substituents that mayor may not be substituted and/or heteroatom containing, and that may bemonocyclic, bicyclic, or polycyclic. The term “alicyclic” is used in theconventional sense to refer to an aliphatic cyclic moiety, as opposed toan aromatic cyclic moiety, and may be monocyclic, bicyclic orpolycyclic.

The terms “halo” and “halogen” are used in the conventional sense torefer to a chloro, bromo, fluoro or iodo substituent.

The term “heteroatom-containing” as in a “heteroatom-containing alkylgroup” (also termed a “heteroalkyl” group) or a “heteroatom-containingaryl group” (also termed a “heteroaryl” group) refers to a molecule,linkage or substituent in which one or more carbon atoms are replacedwith an atom other than carbon, e.g., nitrogen, oxygen, sulfur,phosphorus or silicon, typically nitrogen, oxygen or sulfur. Similarly,the term “heteroalkyl” refers to an alkyl substituent that isheteroatom-containing, the term “heterocyclic” refers to a cyclicsubstituent that is heteroatom-containing, the terms “heteroaryl” andheteroaromatic” respectively refer to “aryl” and “aromatic” substituentsthat are heteroatom-containing, and the like. Examples of heteroalkylgroups include alkoxyaryl, alkylsulfanyl-substituted alkyl, N-alkylatedamino alkyl, and the like. Examples of heteroaryl substituents includepyrrolyl, pyrrolidinyl, pyridinyl, quinolinyl, indolyl, pyrimidinyl,imidazolyl, 1,2,4-triazolyl, tetrazolyl, etc., and examples ofheteroatom-containing alicyclic groups are pyrrolidino, morpholino,piperazino, piperidino, etc.

By “substituted” as in “substituted alkyl,” “substituted aryl,” and thelike, as alluded to in some of the aforementioned definitions, is meantthat in the alkyl, aryl, or other moiety, at least one hydrogen atombound to a carbon (or other) atom is replaced with one or morenon-hydrogen substituents. Examples of such substituents include,without limitation: functional groups such as halo, hydroxyl,sulfhydryl, C₁–C₂₄ alkoxy, C₂–C₂₄ alkenyloxy, C₂–C₂₄ alkynyloxy, C₅–C₂₀aryloxy, acyl (including C₂–C₂₄ alkylcarbonyl (—CO-alkyl) and C₆–C₂₀arylcarbonyl (—CO-aryl)), acyloxy (—O-acyl), C₂–C₂₄ alkoxycarbonyl(—(CO)—O-alkyl), C₆–C₂₀ aryloxycarbonyl (—(CO)—O-aryl), halocarbonyl(—CO)—X where X is halo), C₂–C₂₄ alkylcarbonato (—O—(CO)—O-alkyl),C₆–C₂₀ arylcarbonato (—O—(CO)—O-aryl), carboxy (—COOH), carboxylato(—COO⁻), carbamoyl (—(CO)—NH₂), mono-(C₁–C₂₄ alkyl)-substitutedcarbamoyl (—(CO)—NH(C₁–C₂₄ alkyl)), di-(C₁–C₂₄ alkyl)-substitutedcarbamoyl (—(CO)—N(C₁–C₂₄ alkyl)₂), mono-substituted arylcarbamoyl(—(CO)—NH-aryl), thiocarbamoyl (—(CS)—NH₂), carbamido (—NH—(CO)—NH₂),cyano(—C≡N), isocyano (—N⁺≡C⁻), cyanato (—O—C≡N), isocyanato (—O—N⁺≡C⁻),isothiocyanato, (—S—C≡N), azido (—N═N⁺═N⁻), formyl (—(CO)—H), thioformyl(—(CS)—H), amino (—NH₂), mono- and di-(C₁–C₂₄ alkyl)-substituted amino,mono- and di-(C₅–C₂₀ aryl)-substituted amino, C₂–C₂₄ alkylamido(—NH—(CO)-alkyl), C₆–C₂₀ arylamido (—NH—(CO)-aryl), imino (—CR═NH whereR=hydrogen, C₁–C₂₄ alkyl, C₅–C₂₀ aryl, C₆–C₂₄ alkaryl, C₆–C₂₄ aralkyl,etc.), alkylimino (—CR═N(alkyl), where R=hydrogen, alkyl, aryl, alkaryl,etc.), arylimino (—CR═N(aryl), where R=hydrogen, alkyl, aryl, alkaryl,etc.), nitro (—NO₂), nitroso (—NO), sulfo (—SO₂—OH), sulfonato(—SO₂—O⁻), C₁–C₂₄ alkylsulfanyl (—S-alkyl; also termed “alkylthio”),arylsulfanyl (—S-aryl; also termed “arylthio”), C₁–C₂₄ alkylsulfinyl(—(SO)-alkyl), C₅–C₂₀ arylsulfinyl (—(SO)-aryl), C₁–C₂₄ alkylsulfonyl(—SO₂—alkyl), C₅–C₂₀ arylsulfonyl (—SO₂-aryl), phosphono (—P(O)(OH)₂),phosphonato (—P(O)(O⁻)₂, phosphinato (—P(O)(O⁻)), phospho (—PO₂), andphosphino (—PH₂); and the hydrocarbyl moieties C₁–C₂₄ alkyl (preferablyC₁–C₁₈ alkyl, more preferably C₁–C₁₂ alkyl, most preferably C₁–C₆alkyl), C₂–C₂₄ alkenyl (preferably C₂–C₁₈ alkenyl, more preferablyC₂–C₁₂ alkenyl, most preferably C₂–C₆ alkenyl), C₂–C₂₄ alkynyl(preferably C₂–C₁₈ alkynyl, more preferably C₂–C₁₂ alkynyl, mostpreferably C₂–C₆ alkynyl), C₅–C₂₀ aryl (preferably C₅–C₁₄ aryl), C₆–C₂₄alkaryl (preferably C₆–C₁₈ alkaryl), and C₆–C₂₄ aralkyl (preferablyC₆–C₁₈ aralkyl).

In addition, the aforementioned functional groups may, if a particulargroup permits, be further substituted with one or more additionalfunctional groups or with one or more hydrocarbyl moieties such as thosespecifically enumerated above. Analogously, the above-mentionedhydrocarbyl moieties may be further substituted with one or morefunctional groups or additional hydrocarbyl moieties such as thosespecifically enumerated.

When the term “substituted” appears prior to a list of possiblesubstituted groups, it is intended that the term apply to every memberof that group. For example, the phrase “substituted alkyl and aryl” isto be interpreted as “substituted alkyl and aryl.”

“Optional” or “optionally” means that the subsequently describedcircumstance may or may not occur, so that the description includesinstances where the circumstance occurs and instances where it does not.For example, the phrase “optionally substituted” means that anon-hydrogen substituent may or may not be present on a given atom, and,thus, the description includes structures wherein a non-hydrogensubstituent is present and structures wherein a non-hydrogen substituentis not present. Similarly, the phrase “an optionally present bond” asindicated by a dotted line ----- in the chemical formulae herein meansthat a bond may or may not be present.

In the molecular structures herein, the use of bold and dashed lines todenote particular conformation of groups follows the IUPAC convention. Abond indicated by a broken line indicates that the group in question isbelow the general plane of the molecule as drawn (the “β”configuration), and a bond indicated by a bold line indicates that thegroup at the position in question is above the general plane of themolecule as drawn (the “α” configuration). Single bonds that are notindicated by broken or bold lines may be in either configuration; suchbonds may also be indicated by the conventional symbols

or

.

When referring to a compound of the invention, applicants intend theterm “compound” to encompass not only the specified molecular entity butalso its pharmaceutically acceptable, pharmacologically active analogs,including, but not limited to, salts, esters, amides, prodrugs,conjugates, active metabolites, and other such derivatives, analogs andrelated compounds.

The terms “treating” and “treatment” as used herein refer to reductionin severity and/or frequency of symptoms, elimination of symptoms and/orunderlying cause, prevention of the occurrence of symptoms and/or theirunderlying cause, and improvement or remediation of damage. For example,treatment of a patient by administration of an anti-cancer agent of theinvention encompasses chemoprevention as well as chemotherapy andantiangiogenesis.

By the terms “effective amount” or “therapeutically effective amount” ofa compound of the invention is meant a nontoxic but sufficient amount ofthe drug or agent to provide the desired effect.

By “pharmaceutically acceptable” is meant a material that is notbiologically or otherwise undesirable, i.e., the material may beincorporated into a pharmaceutical composition administered to a patientwithout causing any undesirable biological effects or interacting in adeleterious manner with any of the other components of the compositionin which it is contained. When the term “pharmaceutically acceptable” isused to refer to a pharmaceutical carrier or excipient, it is impliedthat the carrier or excipient has met the required standards oftoxicological and manufacturing testing or that it is included on theInactive Ingredient Guide prepared by the U.S. Food and Drugadministration. “Pharmacologically active” (or simply “active”) as in a“pharmacologically active” derivative or analog, refers to a derivativeor analog having the same type of pharmacological activity as the parentcompound and approximately equivalent in degree.

II. The Novel Compounds:

The compounds of the invention are flavanoids and analogs thereof,having the structure of formula (I)

wherein the various substituents are defined as follows.

R¹, R², and R³ are independently selected from: hydroxyl; sulfhydryl;halo; alkoxy, preferably C₁–C₆ alkoxy, such as methoxy and ethoxy, withmethoxy preferred; aryloxy, preferably C₅–C₁₂ aryloxy, with phenoxypreferred; and aralkyloxy, preferably C₅–C₁₂ aralkyloxy, with benzyloxypreferred. The alkoxy, aryloxy, and aralkyloxy substituents areoptionally heteroatom-containing and/or may be substituted with one ormore, typically one or two substituents. Of course, it will beappreciated that any substituents should not be detrimental to thetherapeutic efficacy of the compound, nor should they be reactive withor otherwise interact adversely with other components of thepharmaceutical composition in which the compound is contained.Substituents include functional groups, hydrocarbyl groups, andcombinations thereof as described in part (I) of this section.

In addition, either R¹ and R², or R² and R³, can be linked to form acyclic structure, which typically, although not necessarily, is selectedfrom five-membered rings, six-membered rings, and fused five-memberedand/or six-membered rings, wherein the cyclic structure is aromatic,alicyclic, heteroaromatic, or heteroalicyclic, and has zero to 4non-hydrogen substituents such as those enumerated above and zero to 3heteroatoms. For example, either R¹ and R², or R² and R³, can be joinedto form a lower alkylene linkage, e.g., —(CH₂)₃— or —(CH₂)₃—, a loweralkylene linkage substituted with a substituent as described above, alower heteroalkylene linkage, e.g., —O—CH₂—O—, —CH₂—O—CH₂, or—CH₂—NH—CH₂, in which case the remaining R group, i.e., R¹ or R³, ishydroxyl, C₁–C₆ alkoxy, aryloxy, or aralkyloxy.

R⁴ is selected from O, S, NR^(x), and CR^(y)R^(z), wherein R^(x), R^(y),and R^(z) are hydrogen or alkyl. Preferably, R^(x), R^(y), and R^(z) arehydrogen, such that R⁴ is O, S, NH or CH₂. In a most preferredembodiment, R⁴ is O.

R⁵ is selected from the group consisting of OH, SH, N(R^(x))₂ whereinthe R^(x) may be the same or different and are selected from hydrogen,alkyl, aryl, and aralkyl, and esters of the structure —O—(CO)—R (i.e.,acyloxy groups) in which R is substituted or unsubstituted alkyl, aryl,or aralkyl. In preferred such esters, R is alkyl, particularly C₁–C₆alkyl, or substituted phenyl. Generally, such acyloxy substituents have2 to 32 carbon atoms, preferably 6 to 32 carbon atoms. Preferred acyloxygroups are aroyloxy groups, with exemplary such groups having thestructure

wherein R¹², R¹³, and R¹⁴ are independently selected from the groupconsisting of hydrogen, hydroxyl, alkyl, alkoxy, aryloxy, andaralkyloxy. Within this group, the most preferred substituents arewherein R¹², R¹³, and R¹⁴ are independently selected from the groupconsisting of hydroxyl, C₁–C₆ alkyl (preferably methyl), C₁–C₆ alkoxy(preferably methoxy), and C₅–C₁₂ aralkyloxy (preferably benzyloxy).

R⁶, R⁷, R⁸, and R⁹ are independently selected from the group consistingof: hydrogen; alkyl, preferably C₁–C₆ alkyl, such as methyl and ethyl,with methyl preferred; alkoxy, preferably C₁–C₆ alkoxy, such as methoxyand ethoxy, with methoxy preferred; aryloxy, preferably C₅–C₁₂ aryloxy,with phenoxy preferred; and aralkyloxy, preferably C₅–C₁₂ aryloxy, withbenzyloxy preferred. Either R⁶ and R⁷, or R⁸ and R⁹, may be linkedtogether to form a cyclic structure selected from five-membered rings,six-membered rings, and fused five-membered and/or six-membered rings,wherein the cyclic structure is aromatic, alicyclic, heteroaromatic, orheteroalicyclic, and has zero to 4 non-hydrogen substituents and zero to3 heteroatoms. Compounds wherein either R⁶ and R⁷, or R⁸ and R⁹, arelinked to form a phenyl or heteroaromatic ring (e.g., pyridinyl,pyrimidinyl, etc.) “fused” to the first are preferred. The phenyl orheteroaromatic ring formed by linkage of R⁶ to R⁷, or of R⁸ to R⁹, maybe further substituted in a similar manner to form a fused tricyclicstructure such as an anthracene, phenanthrene, or benzo[h]quinolinesystem. Particularly preferred such compounds are α-naphthaflavanoids,wherein R⁶ and R⁷ are hydrogen, and R⁸ and R⁹ are linked to form aphenyl ring.

R¹⁰ and R¹¹ are independently selected from the group consisting ofhydrogen, hydroxyl, C₁–C₆ alkyl, C₁–C₆ alkoxy, and halo. Preferably, R¹⁰and R¹¹ are hydrogen.

The aforementioned substituents are defined as indicated with theproviso that the compound of formula (I) excludes EGCG per se, such thatwhen (a) R⁷, R⁹, R¹⁰, and R¹¹ are hydrogen, (b) R¹, R², R³, R⁶, and R⁸are hydroxyl, and (c) R⁴ is O, then (d) R⁵ is other than3,4,5-trihydroxybenzoyloxy or 3,4,5-trimethoxybenzoyloxy.

In compounds of formula (I), if it will be appreciated that because ofthe two chiral centers, four different enantiomers are possible, and thecompound may be in the form of an individual enantiomer or as a racemicmixture of enantiomers. In the following representation, the chiralcenters are represented with a * and the bonds with alternativeconfigurations are indicated by

:

Accordingly, the four possible enantiomers are as follows:

Generally, although not necessarily, the compound of the invention willbe a racemic mixture of the two trans enantiomers. Such a mixture isindicated in the molecular structures herein as follows:

Compounds in the form of a racemic mixture of the two cis enantiomersare represented by the following structure:

Particularly preferred compounds of formula (I) are wherein: R¹, R², andR³ are identical, and are selected from the group consisting of methoxyand benzyloxy; R⁴ is O; R⁵ is OH or an ester substituent R—(CO)—O—wherein R is phenyl substituted at the 3-, 4-, and 5-positions withsubstituents independently selected from the group consisting ofhydroxyl, methyl, methoxy, and benzoyloxy; R⁶ and R⁷ are hydrogen; R⁸and R⁹ are linked together to form a phenyl ring; and R¹⁰ and R¹¹ arehydrogen.

Accordingly, particularly preferred compounds of the invention have thestructure (II)

optimally having the trans structure (III)

wherein a most preferred embodiment, R¹, R², and R³ are methoxy orbenzyloxy.

Specific examples of compounds of the invention include, but are notlimited to, the following.

A compound of the invention may be administered in the form of a salt,ester, amide, prodrug, active metabolite, analog, or the like, providedthat the salt, ester, amide, prodrug, active metabolite or analog ispharmaceutically acceptable and pharmacologically active in the presentcontext. Salts, esters, amides, prodrugs, active metabolites, analogs,and other derivatives of the active agents may be prepared usingstandard procedures known to those skilled in the art of syntheticorganic chemistry and described, for example, by J. March, AdvancedOrganic Chemistry: Reactions, Mechanisms and Structure, 4th Ed. (NewYork: Wiley-Interscience, 1992).

For example, acid addition salts may be prepared from a free base (e.g.,a compound containing a primary amino group) using conventionalmethodology involving reaction of the free base with an acid. Suitableacids for preparing acid addition salts include both organic acids,e.g., acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalicacid, malic acid, malonic acid, succinic acid, maleic acid, fumaricacid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelicacid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid,salicylic acid, and the like, as well as inorganic acids, e.g.,hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid,phosphoric acid, and the like. An acid addition salt may be reconvertedto the free base by treatment with a suitable base. Conversely,preparation of basic salts of any acidic moieties that may be presentmay be carried out in a similar manner using a pharmaceuticallyacceptable base such as sodium hydroxide, potassium hydroxide, ammoniumhydroxide, calcium hydroxide, trimethylamine, or the like. Preparationof esters involves reaction of a hydroxyl group with an esterificationreagent such as an acid chloride. Amides may be prepared from esters,using suitable amine reactants, or they may be prepared from ananhydride or an acid chloride by reaction with ammonia or a lower alkylamine. Prodrugs, conjugates, and active metabolites may also be preparedusing techniques known to those skilled in the art or described in thepertinent literature. Prodrugs and conjugates are typically prepared bycovalent attachment of a moiety that results in a compound that istherapeutically inactive until modified by an individual's metabolicsystem.

In addition, those novel compounds containing chiral centers can be inthe form of a single enantiomer or as a racemic mixture of enantiomers.In some cases, i.e., with regard to certain specific compoundsillustrated herein, chirality (i.e., relative stereochemistry) isindicated. In other cases, it is not, and such structures are intendedto encompass both the enantiomerically pure form of the compound shownas well as a racemic mixture of enantiomers. Preparation of compounds inenantiomerically form may be carried out using an enantioselectivesynthesis; alternatively, the enantiomers of a chiral compound obtainedin the form of the racemate may be separated post-synthesis, usingroutine methodology.

Other derivatives and analogs of the active agents may be prepared usingstandard techniques known to those skilled in the art of syntheticorganic chemistry, or may be deduced by reference to the pertinentliterature.

The compounds of the invention may be readily synthesized usingstraightforward techniques. A preferred synthetic method is theenantioselective synthesis described in Zaveri (2001) Organic Letters3(6):843–846.

III. Pharmaceutical Formulations and Modes of Administration:

The novel compounds may be conveniently formulated into pharmaceuticalformulations composed of one or more of the compounds in associationwith a pharmaceutically acceptable carrier. See Remington: The Scienceand Practice of Pharmacy, 19th Ed. (Easton, Pa.: Mack Publishing Co.,1995), which discloses typical carriers and conventional methods ofpreparing pharmaceutical formulations.

The compounds of the invention may be administered orally, parenterally,rectally, vaginally, buccally, sublingually, nasally, by inhalation,topically, transdermally, or via an implanted reservoir in dosage formscontaining conventional non-toxic pharmaceutically acceptable carriersand excipients. The term “parenteral” as used herein is intended toinclude subcutaneous, intravenous, and intramuscular injection. Theamount of the compound administered will, of course, be dependent on theparticular active agent, the condition or disorder being treated, theseverity of the condition or disorder, the subject's weight, the mode ofadministration and other pertinent factors known to the prescribingphysician. Generally, however, dosage will be in the range ofapproximately 0.001 mg/kg/day to 100 mg/kg/day, more preferably in therange of about 0.1 mg/kg/day to 10 mg/kg/day.

Depending on the intended mode of administration, the pharmaceuticalformulation may be a solid, semi-solid or liquid, such as, for example,a tablet, a capsule, caplets, a liquid, a suspension, an emulsion, asuppository, granules, pellets, beads, a powder, or the like, preferablyin unit dosage form suitable for single administration of a precisedosage. Suitable pharmaceutical compositions and dosage forms may beprepared using conventional methods known to those in the field ofpharmaceutical formulation and described in the pertinent texts andliterature, e.g., in Remington: The Science and Practice of Pharmacy,19^(th) Ed. (Easton, Pa.: Mack Publishing Co., 1995).

As the present compounds are orally active, oral dosage forms aregenerally preferred, and include tablets, capsules, caplets, andnonaqueous solutions, suspensions and or syrups, and may also comprise aplurality of granules, beads, powders or pellets that may or may not beencapsulated. Preferred oral dosage forms are tablets and capsules.

Tablets may be manufactured using standard tablet processing proceduresand equipment. Direct compression and granulation techniques arepreferred. In addition to the active agent, tablets will generallycontain inactive, pharmaceutically acceptable carrier materials such asbinders, lubricants, disintegrants, fillers, stabilizers, surfactants,coloring agents, and the like. Binders are used to impart cohesivequalities to a tablet, and thus ensure that the tablet remains intact.Suitable binder materials include, but are not limited to, starch(including corn starch and pregelatinized starch), gelatin, sugars(including sucrose, glucose, dextrose and lactose), polyethylene glycol,waxes, and natural and synthetic gums, e.g., acacia sodium alginate,polyvinylpyrrolidone, cellulosic polymers (including hydroxypropylcellulose, hydroxypropyl methylcellulose, methyl cellulose,microcrystalline cellulose, ethyl cellulose, hydroxyethyl cellulose, andthe like), and Veegum. Lubricants are used to facilitate tabletmanufacture, promoting powder flow and preventing particle capping(i.e., particle breakage) when pressure is relieved. Useful lubricantsare magnesium stearate, calcium stearate, and stearic acid.Disintegrants are used to facilitate disintegration of the tablet, andare generally starches, clays, celluloses, algins, gums, or crosslinkedpolymers. Fillers include, for example, materials such as silicondioxide, titanium dioxide, alumina, talc, kaolin, powdered cellulose,and microcrystalline cellulose, as well as soluble materials such asmannitol, urea, sucrose, lactose, dextrose, sodium chloride, andsorbitol. Stabilizers, as well known in the art, are used to inhibit orretard drug decomposition reactions that include, by way of example,oxidative reactions.

Capsules are also preferred oral dosage forms, in which case the activeagent-containing composition may be encapsulated in the form of a liquidor solid (including particulates such as granules, beads, powders orpellets). Suitable capsules may be either hard or soft, and aregenerally made of gelatin, starch, or a cellulosic material, withgelatin capsules preferred. Two-piece hard gelatin capsules arepreferably sealed, such as with gelatin bands or the like. See, forexample, Remington: The Science and Practice of Pharmacy, NineteenthEdition. (1995) cited supra, which describes materials and methods forpreparing encapsulated pharmaceuticals.

Oral dosage forms, whether tablets, capsules, caplets, or particulates,may, if desired, be formulated to provide for gradual, sustained releaseof the active agent over an extended time period. Generally, as will beappreciated by those of ordinary skill in the art, sustained releasedosage forms are formulated by dispersing the active agent within amatrix of a gradually hydrolyzable material such as an insoluble plastic(e.g., polyvinyl chloride or polyethylene), or a hydrophilic polymer, orby coating a solid, drug-containing dosage form with such a material.Hydrophilic polymers useful for providing a sustained release coating ormatrix include, by way of example: cellulosic polymers such ashydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose, methyl cellulose, ethyl cellulose, cellulose acetate, andcarboxymethylcellulose sodium; acrylic acid polymers and copolymers,preferably formed from acrylic acid, methacrylic acid, acrylic acidalkyl esters, methacrylic acid alkyl esters, and the like, e.g.copolymers of acrylic acid, methacrylic acid, methyl acrylate, ethylacrylate, methyl methacrylate and/or ethyl methacrylate; and vinylpolymers and copolymers such as polyvinyl pyrrolidone, polyvinylacetate, and ethylene-vinyl acetate copolymer.

Preparations according to this invention for parenteral administrationinclude sterile nonaqueous solutions, suspensions, and emulsions.Examples of nonaqueous solvents or vehicles are propylene glycol,polyethylene glycol, vegetable oils, such as olive oil and corn oil,gelatin, and injectable organic esters such as ethyl oleate. Parenteralformulations may also contain adjuvants such as preserving, wetting,emulsifying, and dispersing agents. The formulations are renderedsterile by incorporation of a sterilizing agent, filtration through abacteria-retaining filter, irradiation, or heat. They can also bemanufactured using a sterile injectable medium.

The compounds of the invention may also be administered through the skinor mucosal tissue using conventional transdermal drug delivery systems,wherein the active agent is contained within a laminated structure thatserves as a drug delivery device to be affixed to the skin. In such astructure, the drug composition is contained in a layer, or “reservoir,”underlying an upper backing layer. The laminated structure may contain asingle reservoir, or it may contain multiple reservoirs. In oneembodiment, the reservoir comprises a polymeric matrix of apharmaceutically acceptable contact adhesive material that serves toaffix the system to the skin during drug delivery. Alternatively, thedrug-containing reservoir and skin contact adhesive are present asseparate and distinct layers, with the adhesive underlying the reservoirwhich, in this case, may be either a polymeric matrix as describedabove, or it may be a liquid or hydrogel reservoir, or may take someother form. Transdermal drug delivery systems may in addition contain askin permeation enhancer.

Although the present compositions will generally be administered orally,parenterally, or transdermally, other modes of administration aresuitable as well. For example, administration may be rectal or vaginal,preferably using a suppository that contains, in addition to the activeagent, excipients such cocoa butter or a suppository wax. Formulationsfor nasal or sublingual administration are also prepared with standardexcipients well known in the art. The pharmaceutical compositions of theinvention may also be formulated for inhalation, e.g., as a solution insaline, as a dry powder, or as an aerosol. Transdermal administration isalso a suitable delivery route for compounds of the invention.

IV. Utility:

The compounds of the invention are useful as chemotherapeutic andchemopreventive agents. The compounds show promise in inhibitingcarcinogenesis, and also in inhibiting the growth of tumor cells thathave already been transformed. In particular, the compounds of theinvention can act as antioxidants and inhibit the production of harmfulfree radicals that can cause DNA damage. In addition, the compounds caninduce apoptosis in tumor cells. Further, the compounds can provideprotective effects for normal cells while inhibiting the growth orkilling cancerous cells

The compounds are useful in the treatment of both primary and metastaticsolid tumors and carcinomas of, without limitation, the breast; colon;rectum; lung; oropharynx; hypopharynx; esophagus; stomach; pancreas;liver; gallbladder; bile ducts; small intestine; urinary tract includingkidney, bladder, and urothelium; female genital tract including cervix,uterus, germ cells, and ovaries; embryo and fetus; male genital tractincluding prostate, seminal vesicles, testes, and germ cells; endocrineglands including thyroid, adrenal, and pituitary; skin (includinghemangiomas, melanomas, sarcomas arising from bone or soft tissues andKaposi's sarcoma); and the brain, nerves, eyes, and meninges (includingastrocytomas, gliomas, glioblastomas, retinoblastomas, neuromas,neuroblastomas, Schwannomas, and meningiomas). The compounds are alsouseful in treating solid tumors arising from hematopoietic malignanciessuch as leukemias, including chloromas, plasmacytomas, plaques andtumors of mycosis fungoides, and cutaneous T-cell lymphoma/leukemia; andlymphomas, including both Hodgkin's and non-Hodgkin's lymphomas. Thecompounds are of particular use in treating cancers of the breast,ovary, prostate, liver, lung, and pancreas, including drug-resistantforms of these cancers. Efficacy against drug-resistant cancersrepresents an important advance in the art, as a major problem affectingthe efficacy of chemotherapy regimens is the evolution of cancer cellsthat, upon exposure to a chemotherapeutic drug, become resistant to amultitude of structurally unrelated drugs and therapeutic agents.

It is to be understood that while the invention has been described inconjunction with the preferred specific embodiments thereof, thedescription above as well as the examples that follow are intended toillustrate and not limit the scope of the invention. Other aspects,advantages and modifications within the scope of the invention will beapparent to those skilled in the art to which the invention pertains.

All patents, patent applications, journal articles and other referencecited herein are incorporated by reference in their entireties.

V. Experimental:

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how toprepare and use the compounds disclosed and claimed herein. Efforts havebeen made to ensure accuracy with respect to numbers (e.g., amounts,temperature, etc.) but some errors and deviations should be accountedfor. Unless indicated otherwise, parts are parts by weight, temperatureis in ° C. and pressure is at or near atmospheric.

¹H and ¹³C NMR spectra were recorded on a Varian Gemini 300 MHzspectrometer (at 300 MHz and 75 MHz, respectively) and are internallyreferenced to chloroform at δ 7.27 ppm. Data for ¹H NMR are reported asfollows: chemical shift (δ ppm), multiplicity (br=broad, s=singlet,d=doublet, t=triplet, q=quartet, m=multiplet, exch=proton exchanged onaddition of D₂O), coupling constant (Hz), integration, and assignment.Data for ¹³C are reported in terms of chemical shift. IR spectra wererecorded on a Perkin-Elmer 1610 spectrometer and are reported in termsof frequency of absorption (cm⁻¹). Mass spectra were obtained using aThermoFinnigan LCQ Duo LC/MS/MS instrument and an electrosprayionization probe. Thin-layer chromoatgraphy was run on Analtech Uniplatesilica gel TLC plates. Flash chromatography was carried out using silicagel, Merck grade 9385, 230–400 mesh. Reverse phase chromatography wascarried out using C18 reverse phase silica gel, purchased from Baker.Microwave irradiation of reaction mixtures were carried out in cappedvials in the Personal Chemistry Microwave Irradiator, Smith Creator.

2′,4′,6′-trihydroxyacetophenone, 3,4,5-trimethoxybenzaldehyde,3,5-dimethylphenol and methyl gallate were purchased from AldrichChemical Company. 3,5-dimethoxy-2-hydroxyacetophenone and3,5-dimethyl-4-benzyloxybenzoic acid was purchased from Lancaster. DessMartin periodinane was purchased from Omega Inc. (Canada).Tetrahydrofuran was distilled from benzophenone ketyl before use.

EXAMPLE 1 SYNTHESIS OFtrans-5,7-DIHYDROXY-2-(3,4,5-TRIMETHOXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,3,4,5-TRIHYDROXY-BENZOIC ACID ESTER (SR 13194)

The above compound, a B-ring analog of EGCG, was synthesized accordingto Scheme 1 (FIG. 1), as follows:

(a) Preparation of 4′,6′-bisbenzyloxy-2′-hydroxyacetophenone (2) from2′,4′,6′-trihydroxyacetophenone (1): A mixture of2′,4′,6′-trihydroxyacetophenone (20 g, 0.12 mol, dried in the oven at140° C.) and anhydrous potassium carbonate (50 g, 0.36 mol) inhexamethylphosphoramide (160 mL) was treated with benzyl chloride (30mL, 0.26 mol), and the suspension heated at 90–93° C., under an argonatmosphere, for 1.5 h. The mixture was then cooled and filtered. Thefiltrate was added to 300 mL ice-cold water and acidified to pH 4 with6N HCl. The resulting suspension was heated to 70° C. for 1 h, and thencooled at 4° C. for 16 h. The deposited sticky solid was filtered offand washed with water. This solid was air dried, and recrystallized fromboiling methanol/acetone (2:1). Cooling the solution afforded theproduct 8 as off-white crystals (27.55 g, 66.5% yield). ¹H NMR (300 MHz,CDCl₃): δ 2.56 (s, 3H, CH₃), 5.06 (s, 4H, CH₂), 6.10 and 6.16 (2s, 2H,3′,5′-Ar—H), 7.40 (m, 10H, Ar—H), 14.01 (s, 1H, OH).

(b) Preparation of chalcone 4: A mixture of the acetophenone 2 (2 g,5.75 mmol) and 3,4,5-trimethoxybenzaldehye (1.69 g, 8.62 mmol) in 10%w/v solution of potassium hydroxide in ethanol was stirred at roomtemperature for 40 h. The resulting solution deposited a yellow solid,which was collected by filtration and washed with cold ethanol. Thesolid was dried under high vacuum to afford 2.38 g of product 4 as thefirst crop. The ethanol filtrate still contained some product and wasconcentrated down and cooled to afford 0.47 g as a second crop. Thecombined yield of the two crops was 94%. TLC:hexanes: methylenechloride:ethyl acetate (3:1:1): Rf=0.60; ¹H NMR (300 MHz, CDCl₃): δ 3.67(s, 6H, OCH₃), 3.90 (s, 3H, OCH₃), 6.19 (d, J=2.34 Hz, 1H, 8-H), 6.26(d, J=2.34 Hz, 1H, 6-H), 6.62 (s, 2H, 2′,6′-H), 7.26–7.45 (2m, 10H,Ar—H), 7.71 (d, 1H, CH═CH), 7.82 (d, 1H, CH═CH), 14.23 (s, 1H, OH).

(c) Preparation of the 3-flavene 5: To a solution of the chalcone 4(2.94 g, 5.59 mmol) in tetrahydrofuran (30 mL) and ethanol (30 mL) wasadded sodium borohydride (212 mg, 5.59 mmol) at room temperature. Thesolution was stirred at gentle reflux for 16 hours after which nostarting material was observed by TLC. The solution was cooled andevaporated to dryness and the residue was redissolved in methylenechloride. The organic solution was washed with water and brine, dried(MgSO₄) and purified by flash chromatography, using stepwise elutionwith hexanes:ethyl acetate (95:5 to 80:20), to elute the pure product.The fractions containing pure product were pooled, evaporated and driedunder vacuum to yield 2.09 g of a colorless thick oil (73% yield). TLC:hexanes:methylene chloride:ethyl acetate (3:1:1): Rf=0.63; ¹H NMR (300MHz, CDCl₃): δ 3.83 and 3.85 (two s, 9H, OCH₃), 4.98 (s, 2H, OCH₂Ph),5.04 (s, 2H, OCH₂ Ph), 5.58 (dd, 1H, 3-H), 5.85 (m, 1H, 2-H), 6.15Ar—H).

(d) Preparation of the 2,3-trans 3-flavanol 6: To a solution of the3-flavene 5 (2.12 g, 4.17 mmol) in tetrahydrofuran (20 mL) at 0° C.under argon, was added a 1M solution of borane in tetrahydrofuran (33.35mL, 33.35 mmol) via a dropping funnel. The solution was stirred at roomtemperature for 4 hours during which time it turned from yellow tocolorless. The reaction showed no residual starting material and wascooled down to 0° C. and quenched by dropwise addition of water (2 mL).3N NaOH (11.8 mL, 35.45 mmol) and 50% H₂O₂ (2.42 mL, 35.45 mmol) werethen added and the solution was warmed to 65° C. for 1 hour and allowedto stir at room temperature for 16 h. The reaction was then diluted withethyl acetate and washed with water and brine. The organic layer wasdried (MgSO₄) and evaporated to afford 2.37 g of white solid as crudeproduct. This was purified by flash chromatography, eluting stepwisewith hexanes:ethyl acetate (9:1 to 7:3). Fractions containing pureproduct were pooled and evaporated to afford 0.87 g (40%) of 6 as atranslucent white solid. TLC: hexanes:ethyl acetate (6:4): Rf=0.38; ¹HNMR (300 MHz, CDCl₃): δ 2.69 (dd, 1H, 4-H axial), 3.10 (dd, 1H, 4-Hequatorial), 3.85 and 3.87 (two s, 9H, OCH₃), 4.06 (m, 1H, 3-H), 4.62(d, 1H, 2-H), 5.00 (s, 2H, CH ₂OPh), 5.04 (s, 2H, CH ₂OPh), 6.20 and6.28 (2d, 2H, 6, 8-Ar—H), 6.67 (s, 2H 2′, 6′-Ar—H). 7.36–7.41 (m, 10H,Ar—H).

(e) Preparation of SR 13194 from 6: 3,4,5-Tribenzyloxybenzoic acid wasfirst converted to its acid chloride by heating a neat solution of theacid (0.375 g, 0.85 mmol) with thionyl chloride (0.99 mL, 13.6 mmol) at65° C. for 3.5 h. The excess thionyl chloride was evaporated and theresidue co-evaporated with hexanes (2×10 mL) and benzene (2×10 mL). Thesolid acid chloride was dissolved in methylene chloride and addeddropwise to a solution of the alcohol 6 (150 mg, 0.28 mmol) and DMAP(51.3 mg, 0.42 mmol) in pyridine (4 mL). The reaction mixture wasstirred at room temperature for 16 hours after which it was diluted withmethylene chloride and washed with 0.1 N HCl (2×100 mL), water,saturated aqueous NaHCO₃ and brine. The organic layer was evaporated toafford 0.497 g of crude ester, which was purified by flashchromatography, eluting the product with hexanes:ethyl acetate (90:10 to7:3) to afford 0.130 g (48%) of pure ester product as a colorlesssemisolid. TLC: hexanes:ethyl acetate (6:4): Rf=0.65; ¹H NMR (300 MHz,CDCl₃): δ 2.89 (dd, 1H, 4-H), 3.10 (dd, 1H, 4-H), 3.72 (s, 6H, OCH₃),3.79 (s, 3H, OCH₃), 5.04 (m, 11H, OCH₂Ph and 3-H), 5.52 (m, 1H, 2-H),6.31 (d, 2H, 6,8-Ar—H), 6.60 (s, 2H, 2′,6′-Ar—H), 7.22–7.37 (m, 25H,Ar—H).

The benzyl protected ester above was dissolved in dioxane (10 mL) andtreated with 10% Pd on carbon (70 mg) and hydrogenated at atmosphericpressure using a hydrogen balloon for 5 hours. The mixture was thenfiltered through an acrodisc filter mounted on a syringe. The filter waswashed with methanol and ethyl acetate. The filtrate was evaporated todryness and the crude product was purified by reverse-phase silica gelchromatography over C18 silica gel, eluting with H₂O:methanol (90:10 to40:60). Fractions containing pure product were concentrated andlyophilized to afford 10 mg of pure SR 13194 as a cream powder. ¹H NMR(300 MHz, acetone-d₆): δ 2.82 (m, 1H, 4-H), 3.10 (m, 1H, 4-H), 3.81 (s,3H, OCH ₃), 3.73 and 3.81 (2s, 9H, OCH ₃), 5.20 (m, 1H, 2-H), 5.45 (m,1H, 3-H), 6.05 (d, 1H, 8-H), 6.15 (d, 1H, 6-H), 6.83 (s, 2H,2′,6′-Ar—H), 7.10 (s, 2H, 2″,6″-Ar—H), 8.14 (s, OH), 8.22 (m, OH), 8.25(s, OH), MS (DCI-NH₃): 501 (M+H). HRMS: Calcd. 501.4634, Found.501.1376.

EXAMPLE 2 SYNTHESIS OFcis-5.7-DIHYDROXY-2-(3,4,5-TRIMETHOXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,3,4,5-TRIHYDROXY-BENZOIC ACID ESTER (SR 13195)

The above compound, also a B-ring analog of EGCG, was synthesizedaccording to Scheme 1 (FIG. 1), as follows:

(a) Preparation of 3-flavanone 7: To a hazy suspension of Dess Martinperiodinane (1 g, 2.295 mmol) in dry methylene chloride (10 mL) wasadded a solution of trans 3-flavanol 6 (0.81 g, 1.53 mmol) in methylenechloride (10 mL) at room temperature. The resulting purple solution wasstirred at room temperature for 4 h, after which it was poured into asaturated solution of sodium bicarbonate (60 mL) containing 7equivalents of sodium thiosulfate (16.06 mmol, 3.98 g) and stirred for10 minutes. The resulting brown solution was extracted with methylenechloride and the organic layer washed with water and brine, and dried(MgSO₄). The filtered solution was then evaporated to afford the crude3-flavanone 7, which was purified by flash chromatography, usinghexanes:ethyl acetate (95:5 to 8:2) to afford 0.432 g (53%) of pureproduct as a thick, colorless oil. TLC: hexanes:methylene chloride:ethylacetate (3:1:1): Rf=0.39; ¹H NMR (300 MHz, CDCl₃): δ 3.60 (dd, 2H, 4-Hαand β), 3.79 (s, 6H, OCH₃), 3.82 (s, 3H, OCH₃), 5.02 (s, 2H, OCH₂Ph),5.04 (s, 2H, OCH₂Ph), 5.29 (s, 1H, 2-H), 6.32 and 6.41 (2d, 2H,6,8-Ar—H), 6.58 (s, 2H, 2′,6′-Ar—H), 7.37–7.40 (m, 10H, Ar—H).

(b) Preparation of the 2,3-cis 3-flavanol 8: To a solution of the3-flavanone 7 (0.43 g, 0.82 mmol) in dry tetrahydrofuran (10 mL), cooledin a dry ice bath, was added a 1M solution of L-selectride intetrahydrofuran (7.39 mL, 7.39 mmol) via a syringe under argon. The dryice bath was then removed and the solution was allowed to stir at roomtemperature for 8 h. The reaction was again cooled in dry ice, and tothis was added 3N NaOH (3.55 mL, 10.66 mmol) and 50% H₂O₂ (0.72 mL,10.66 mmol). The solution was stirred for 1 hour at room temperature andthen diluted with ethyl acetate. The organic solution was washed withsaturated aqueous NaHCO₃, water and brine, dried (MgSO₄), and evaporatedto give the crude alcohol. This was purified by flash chromatography,eluting with hexanes:ethyl acetate (85:15 to 7:3) to afford 0.242 g(52%) of pure product as a greenish yellow foamy solid. TLC:hexanes:ethyl acetate (3:1:1): Rf=0.16 ¹H NMR (300 MHz, CDCl₃): δ 1.75(d, 1H, OH), 2.95 (dd, 1H, 4-H), 3.05 (dd, 1H, 4-H), 3.86 (s, 3H, OCH₃),3.89 (s, 6H, OCH₃), 4.30 (m, 1H, 3-H), 4.95 (broad s, 1H, 2-H), 5.02 (s,2H, CH₂OPh), 5.04 (s, 2H, CH ₂OPh), 6.28 and 6.31 (two d, 2H, 6,8-Ar—H),6.75 (s, 2H, 2′,6′-Ar—H), 7.36–7.41 (m, 10H, Ar—H).

(c) Preparation of SR 13195 from the 2,3-cis-3-flavanol 8: Theesterification of the 3-flavanol 8 to SR 13195 was carried out asdescribed in Example 1, part (e), with respect to the synthesis of SR13194, using 0.25 g (0.57 mmol) of 3,4,5-tribenzyloxybenzoic acid and100 mg (0.19 mmol) of the cis 3-flavanol 8 to afford 79 mg (44%) yieldof the benzyl protected ester after flash chromatography. TLC:hexanes:ethyl acetate (6:4): Rf=0.51; ¹H NMR (300 MHz, CDCl₃): δ 3.10(m, 2H, 4-H), 3.53 (s, 6H, OCH₃), 3.80 (m, 3H, OCH₃), 5.04 (m, 11H,OCH₂Ph and 3-H), 5.69 (m, 1H, 2-H), 6.35 (d, 1H, 8-Ar—H), 6.41 (d, 1H,6-Ar—H), 6.60 (s, 2H, 2′,6′-Ar—H), 7.25–7.38 (m, 25H, Ar—H). The esterwas deprotected by catalytic hydrogenation as described in Example 1,part (e), using 172 mg of the ester and 100 mg of 10% Pd on carbon indioxane (10 mL). The crude product was purified by reverse phasechromatography to afford 24 mg of pure SR 13195 as a fluffy creampowder. MS (DCI-NH₃): 501 (M+H).

EXAMPLE 3 SYNTHESIS OFcis-5,7-DIHYDROXY-2-(3,4,5-TRIMETHOXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,4-HYDROXY-3,5-DIMETHYL-BENZOIC ACID ESTER (SR 13196)

The above compound, a B- and D-ring analog of EGCG, was synthesizedaccording to Scheme 1 (FIG. 1), as follows:

The esterification of the 3-flavanol 8 to SR 13196 was also carried outas described in Example 1, part (e). The acid chloride of3,5-dibenzyloxy-4-methylbenzoic acid (0.276 g, 1.08 mmol) was preparedas described for SR 13194 and added to a solution of 8 (142 mg, 0.27mmol) and dimethylamino pyridine (DMAP; 49.5 mg, 0.405 mmol) in drypyridine. The mixture was stirred for 16 hours and recharged with acidchloride (1.08 mmol) and stirred for an additional 18 h, after which allof 8 was consumed. The reaction was poured into 1N HCl (25 mL) andextracted with methylene chloride. The organic layer was washed withwater, saturated NaHCO₃, and brine. The organic layer was dried (MgSO₄)and evaporated to yield a crude product, which was purified by flashchromatography, eluting the pure ester with methylene chloride:ethylacetate (99:1) to afford 110 mg (53%) of the benzyl protected esterafter flash chromatography. TLC: hexanes:ethyl acetate (6:4): Rf=0.53;¹H NMR (300 MHz, CDCl₃): δ 2.26 (s, 6H, CH3), 3.11 (m, 2H, 4-H), 3.74(s, 6H, OCH3), 3.80 (m, 4H, OCH3 and 3-H), 4.80 (s, 2H, 2″, 6″-H), 5.05(m, 6H, CH2OPh), 5.65 (m, 1H, 2-H), 6.32 (two d, 2H, 6,8-H), 6.71 (s,2H, 2′,6′-H), 7.35–7.42 (m, 15H, Ar—H).

The ester was deprotected by catalytic hydrogenation as described inExample 1, part (e), using 110 mg of the ester and 50 mg of 10% Pd blackin dioxane (10 mL). The crude product was purified by normal phase flashchromatography, eluting the product with methylene chloride:ethylacetate (9:1 to 8:2). Fractions containing pure product were evaporatedand dried to afford 53 mg of pure SR 13196 as a flaky crystalline whitesolid. TLC: methylene chloride:ethyl acetate (7:3): Rf=0.33; ¹H NMR (300MHz, CDCl₃): δ 2.20 (s, 6H, CH₃), 3.02 (m, 2H, 4-H), 3.65 (s, 3H, OCH₃),2.79 (s, 6H, OCH₃), 5.21 (s, 1H, 3-H), 5.60 (broad s, 1H, 2-H), 6.05 (m,2H, 6,8-Ar—H), 6.90 (s, 2H, 2′,6′-Ar—H), 7.57 (s, 2H, 2″,6″-Ar—H), 7.98(s, 1H, OH), 8.25 (s, 1H, OH). MS (ESI): 495 (M−H); HRMS (M+H): Calcd.497.5188, Found. 497.1826.

EXAMPLE 4 SYNTHESIS OFcis-5,7-DIHYDROXY-2-(3,4,5-TRIHYDROXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,4-METHOXY-3,5-DIMETHYL-BENZOIC ACID ESTER (SR 13197)

The above compound, a D-ring analog of EGCG, was synthesized accordingto Scheme 2 (FIG. 2), as follows:

(a) Preparation of 3,4,5-tribenzyloxybenzaldehyde 12 from methyl gallate9: A mixture of methyl gallate 9 (10 g, 53 mmol) and potassium carbonate(45 g, 320 mmol) in DMF (120 mL) was treated with benzyl bromide (210mmol, 25.7 mL) and stirred at 40° C. under an argon atmosphere for 24 h.The reaction mixture was filtered and the filtrate evaporated todryness. The residue was dissolved in minimum amount of methylenechloride and diluted with an equal volume of hexanes and loaded onto ashort silica gel pad in a sintered glass funnel. The silica was elutedwith hexanes (300 mL) to remove excess benzyl bromide and the eluantdiscarded. The product was then eluted with methylene chloride:hexanes(1:1, 300 mL) followed by methylene chloride (500 mL) and the eluantscombined and evaporated to afford pure benzyl product 10 as an off-whitesolid (100% yield). ¹H NMR (300 MHz, CDCl₃): δ 3.88 (s, 3H, CH₃), 5.11and 5.13 (2s, 6H, OCH₂), 7.35–7.41 (m, 17H, Ar—H).

To a solution of 3,4,5-tribenzyl-methyl gallate 10 (10 g, 22 mmol) indry tetrahydrofuran (75 mL) was added solid lithium aluminum hydride(1.25 g, 33 mmol) in small portions. The suspension was heated to refluxunder argon for 2 h. The reaction was cooled to 0° C. and carefullyquenched with the dropwise addition of water. The slurry was thenextracted with ethylacetate/hexanes. The organic solution was dried withsaturated brine, followed by anhydrous magnesium sulfate, filtered andevaporated to afford the pure alcohol 11 as a white solid (8.9 g, 95%yield). ¹H NMR (300 MHz, CDCl₃): δ 4.6 (d, 2H, CH₂), 5.04 and 5.11 (2s,6H, OCH₂), 6.67 (s, 2H, 2,6-Ar—H), 7.25–7.43 (m, 15H, Ar—H).

To a solution of 3,4,5-tribenzyloxy-benzyl alcohol 11 (8.9 g, 21 mmol)in methylene chloride (200 mL) at 0° C. was added pyridiniumchlorochromate (5.43 g, 25 mmol) in small portions with vigorousstirring. The cooling was discontinued and reaction stirred at roomtemperature for 4 h. The dark brown suspension was filtered over a longpad of silica gel in a sintered glass funnel, and eluted with methylenechloride, until all the pure product eluted out. The organic filtratewas evaporated down to give the pure product 12 as a soft white solid(8.1 g, 91.5% yield). ¹H NMR (300 MHz, CDCl₃): δ 5.16 (s, 6H, OCH₂),7.18 (s, 2H, 2,6-Ar—H), 7.26–7.41 (m, 15H, Ar—H), 9.80 (s, 1H, CHO).

(b) Preparation of chalcone 13: A mixture of4,6-dibenzyloxy-2-hydroxy-acetophenone 2 (15 g, 0.043 mol) and3,4,5-tribenzyloxybenzaldehyde 12 (20.1 g, 0.047 mol) in ethanol (400mL) was placed in a three-necked flask fitted with an overhead stirrerand condenser. Piperidine (80 mL) was then added and the mixture washeated to reflux for 24 h. A yellow solid precipitated out. The reactionmixture was cooled and filtered to afford a yellow solid, which waswashed with cold ethanol and dried to afford the chalcone 13 as a yellowsolid (60% yield). TLC: methylene chloride: Rf=0.51; ¹H NMR (300 MHz,CDCl₃): δ 4.87 (s, 4H, CH ₂OPh), 5.12 (m, 6H, CH ₂OPh), 6.18 (d, 1H,3′-Ar—H), 6.25 (d, 1H, 5′-Ar—H), 6.70 (s, 2H, 3, 6-Ar—H), 7.19–7.45 (m,25H, OBn-Ar—H), 7.66 (d, 1H, C(O)—CH═CH—), 7.78 (d, 1H, C(O)—CH═CH—),14.21 (s, 1H, OH). ¹³C NMR (75 MHz, CDCl₃): δ 70.39, 71.20, 75, 26,93.07, 95.22, 108.44, 127.10–128.83, 130.84, 135.80, 135.94, 136.89,142.46, 152.92, 161.55, 165.24, 168.17, 192.63. Anal. Calcd. forC₅₀H₄₂O₇ (754.88): C, 79.56, H, 5.61; Found: C, 79.47, H, 5.64.

(c) Preparation of 3-flavene 14: The 3-flavene 14 was synthesized by thesame procedure as for the synthesis of 3-flavene 5, (Scheme 1), usingNaBH₄/THF/EtOH. The 3-flavene was typically isolated in 50–60% yield asa colorless thick liquid. TLC: methylene chloride:hexanes (8:2):Rf=0.53; ¹H NMR (300 MHz, CDCl₃): δ 4.99, 5.03, 5.05, 5.09 (4s, 10 H, CH₂OPh), 5.53 (dd, J=9.95 and 3.29 Hz, 1H, 3-H), 5.72 (dd, J=3.24 and 1.95Hz, 1H, 2-H), 6.13 and 6.20 (2d, J=2.17, 2H, 6,8-Ar—H), 6.78 (s, 2H,2′,6′-Ar—H), 6.86 (dd, J=9.86 and 1.57 Hz, 1H, 4-H), 7.25–7.41 (m, 25H,Ar—H).

(d) Preparation of 2,3-trans 3-flavanol 15: The trans 3-flavanol 14 wassynthesized by the same procedure as for the synthesis of flavanol 6(Scheme 1), using BH₃/THF. The trans 3-flavanol was typically isolatedin 70% yield as a white solid. TLC: methylene chloride:hexanes (8:2):Rf=0.13; ¹H NMR (300 MHz, CDCl₃): δ 2.64 (dd, J=16.45 and 8.88 Hz, 1H,4-H, axial), 3.10 (dd, J=16.42 and 5.68 Hz, 1H, 4-H equatorial), 3.96(m, 1H, 3-H), 4.61 (d, J=8.12 Hz, 1H, 2-H), 5.05 (m, 10H, CH ₂OPh), 6.20and 6.28 (2s, 2H, 6,8-Ar—H), 6.73 (s, 2H, 2°,6′-Ar—H), 7.25–7.41 (m,25H, Ar—H). MS (DCI-NH₃): 757 (M+H), 774 (M+NH₄).

(e) Preparation of 3-flavanone 16: The 3-flavanone 16 was synthesized byDess Martin oxidation of the 3-flavanol 15 in an identical manner as forthe synthesis of 3-flavanone 7 (Scheme 1), in 50–60% yields. TLC:methylene chloride: Rf=0.37; ¹H NMR (300 MHz, CDCl₃): δ 3.41 (d, J=21.3Hz, 1H, 4-H), 3.39 (d, J=21.3 Hz, 1H, 4-H), 5.03 (m, 10H, CH ₂OPh), 5.24(s, 1H, 2-H), 6.35 and 6.37 (2s, 2H, 6,8-Ar—H), 6.67 (s, 2H,2′,6′-Ar—H), 7.25–7.41(m, 25H, Ar, H).

(f) Preparation of the 2,3-cis 3-flavanol 17: The cis 3-flavanol 17 wasprepared by the L-selectride reduction of the 3-flavanone 16 in the samemanner as for the synthesis of flavanol 8 (Scheme 1) in 60–70% yields.TLC: hexanes:ethyl acetate (8:2): Rf=0.27; ¹H NMR (300 MHz, CDCl₃): δ1.61 (broad s, 1H, OH), 2.92 (dd, J=17.13 and 4.40 Hz, 1H, 4-H), 3.02(dd, J=17.64 and 2.27 Hz, 1H, 4-H), 4.21 (m, 1H, 3-H), 4.90 (broad s,1H, 2-H), 5.03 (s, 4H, CH ₂OPh), 5.06 (s, 2H, CH ₂OPh), 5.14 (s, 4H, CH₂OPh), 6.28 (s, 2H, 6,8-Ar—H), 6.81 (s, 2H, 2′, 6′-Ar—H), 7.25–7.41 (m,25H, Ar—H). MS (DCI-NH₃): 757 (M+H), 774 (M+NH₄).

(g) Preparation of SR 13197 from cis 3-flavanol 17: To a solution of4-benzyloxy-3,5-dimethylbenzoic acid (0.138 g, 0.53 mmol), EDC (305 mg,1.59 mmol), HOBt (143.23 mg, 1.06 mmol), DMAP (129.50 mg, 1.06 mmol) andtriethylamine (0.185 mL, 1.325 mmol) in methylene chloride (7 mL) wasadded a solution of 17 (200 mg, 0.265 mmol) in methylene chloride (3mL). The solution was stirred at room temperature for 60 h, after whichno starting flavanol was seen by TLC. The reaction was diluted withmethylene chloride (100 mL) and washed with 0.1N HCl, saturated NaHCO₃,water and brine. The organic layer was dried (MgSO₄) and evaporated togive 0.36 g of crude product which was purified by flash chromatography,eluting the product as a pure fraction, with methylene chloride:hexanes(7:3). Fractions containing pure product were pooled and evaporated toafford 0.166 g (63%) yield of the protected ester intermediate. TLC:hexanes:ethyl acetate (6:4): Rf=0.72; ¹H NMR (300 MHz, CDCl₃): δ 2.23(s, 6H, CH₃), 3.11 (m, 2H, 4-H), 4.59 (d, J=2.4 Hz, 3H), 4.99 (m, 12H,CH ₂OPh,), 5.62 (s, 1H, 2-H), 6.31 (d, J=2.4 Hz, 8-H), 6.35 (d, J=2.4Hz, 6-H), 6.82 (s, 2H, 2′,6′-H), 7.34 (m, 30H, Ar—H), 7.68 (s, 2H,2″,6″-H); MS (ESI) 1017 (M+Na).

SR 13197 was then prepared from the protected ester above by catalytichydrogenation with Pd black using the same procedure as for thesynthesis of SR 13196 (Scheme 1). ¹H NMR (300 MHz, acetone-d₆): δ 2.21(s, 3H, CH₃), 2.26 (s, 3H, CH₃), 2.98–3.01 (m, 2H, 4-H), 5.09 (s, 1H,3-H), 5.46–5.49 (m, 1H, 2-H), 6.02 (d, J=2.4 Hz, 1H, 8-H), 6.04 (d,J=2.4 Hz, 1H, 6-H), 6.63 (s, 2H, 2″,6″-H), 7.52 (s, 2H, 2′,6′-H), 7.65(s, 2H, OH).

EXAMPLE 5 SYNTHESIS OFtrans-5,7-DIMETHOXY-2-(3,4,5-TRIHYDROXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,3,4,5-TRIHYDROXY-BENZOIC ACID ESTER (SR 13198)

The above compound, an A-ring analog of EGCG, was synthesized accordingto Scheme 3 (FIG. 3), as follows:

(a) Preparation of(2E)-1-(2-hydroxy-4,6-dimethoxyphenyl)-3-(3,4,5-tribenzyloxyphenyl)prop-2-en-1-one(19): To a suspension of NaH (1.63 g, 40.78 mmol, 60% in mineral oilw/w) in 50 mL of freshly distilled DMF, was portion wise added4,6-dimethyoxy-2-hydroxyacetophenone 18 (5 g, 25.50 mmol) at roomtemperature. The mixture was left to stir for 1 hour until all H₂evolution was ceased. Tribenzyloxybenzaldehyde 12 (13 g, 30.60 mmol) wasthen added all at once and the mixture continued to stir for anadditional 30 minutes, after which the solution gradually became darkred. The mixture was diluted with water and a yellow solid precipitatedfrom solution. The solid thus obtained was filtered off and washedseveral times with cold methanol, and dried under reduced pressure (15mmHg at room temperature) overnight to provide 14.12 g (92% yield) ofpure chalcone 19. ¹H NMR (300 MHz, CDCl₃): δ 3.81 (s, 3H, OCH₃), 3.84(s, 3H, OCH₃), 5.12 (s, 2H, OCH₂Ph), 5.16 (s, 4H, OCH₂Ph), 5.94 (d,J=2.7 Hz, 1H, CH═CH), 6.10 (d, J=2.7 Hz, 1H, CH═CH), 6.88 (s, 2H,2′,6′-Ar—H), 7.26–7.44 (m, 17H, Ar—H, 6,8-H), 14.25 (s, 1H, OH). ¹³CNMR(CDCl₃): 55.59, 55.80, 71.34, 75.31, 91.29, 93.83, 106.34, 108.32,126.87, 127.31, 127.46, 127.94, 127.98, 128.20, 128.58, 131.13, 136.86,137.55, 140.90, 142.30, 153.02, 162.41, 166.19, 168.34, 192.37.

(b) Preparation of5,7-dimethoxy-2-(3,4,5-tribenzyloxyphenyl)-2H-chromene (20)

The 3-flavene 20 was synthesized by the same procedure as for thesynthesis of 3-flavene 5, (Scheme 1), using NaBH₄/THF/EtOH. 20 wasisolated in 52% yield as a white solid after flash chromatography usingmethylene chloride. ¹H NMR (300 MHz, CDCl₃): δ 3.75 (s, 3H, OCH₃), 3.78(s, 3H, OCH₃), 5.02 (s, 2H, OCH₂Ph, 5.09 (s, 4H, OCH₂Ph), 5.52 (dd,J=3.6, 9.6 Hz, 1H, 4-H), 5.69–5.72 (m, 1H, 3-H), 6.05 (s, 2H,2′,6′-Ar—H), 6.76 (s, 2H, 6,8-Ar—H), 6.78 (dd, J=1.8, 9.6 Hz, 1H, 2-H),7.24–7.43 (m, 15H, Ar—H). ¹³C NMR (CDCl₃): 55.61, 55.86, 71.46, 75.43,77.52, 92.15, 94.01, 104.59, 107.21, 119.20, 119.85, 127.78, 127.97,128.06, 128.36, 128.66, 128.74, 136.69, 137.29, 138.14, 138.79, 153.15,155.06, 156.52, 161.53.

(c) Preparation of(2,3-trans)-5,7-dimethoxy-2-(3,4,5-tribenzyloxyphenyl)chroman-3-ol (21):The flavanol 21 was synthesized by the same hydroboration/oxidationsequence from 20, as used for 6, yielding exclusively the 2,3-transalcohol 21 as a white solid in 83% yield after silica gelchromatography, eluting 30% ethyl acetate in hexanes. ¹H NMR (300 MHz,CDCl₃): δ 1.63 (d, J=3.6 Hz, 1H, OH), 2.55 (dd, J=8.7, 16.5 Hz, 1H,4-H), 2.98 (dd, J=5.7, 16.5 Hz, 1H, 4-H), 3.74 (s, 3H, OCH₃), 3.78 (s,3H, OCH₃), 3.90–4.00 (m, 1H, 3-H), 4.59 (d, J=7.8 Hz, 1H, 2-H), 5.05 (s,2H, OCH₂Ph), 5.08 (s, 2H, OCH₂Ph), 5.09 (s, 2H, OCH₂Ph), 6.10 (d, J=2.4Hz, 1H, 8-H), 2.4 Hz, 1H, 8-H), 6.12 (d, J=2.4 Hz, 1H, 6-H), 6.73 (s,2H, 2′,6′-H), 7.22–7.43 (m, 15H, Ar—H). ¹³C NMR (CDCl₃) 27.57, 55.61,55.74, 68.50, 71.49, 75.42, 77.43, 82.04, 92.23, 93.24, 101.78, 107.05,127.78, 128.05, 128.16, 128.39, 128.71, 128.76, 133.57, 137.09, 138.01,153.28, 155.30, 159.00, 160.00.

(d) Preparation of SR 13198: The hexabenzyloxy-protected precursor of SR13198 was prepared from 21 as follows. A mixture of 21 (400 mg, 0.66mmol), 3,4,5-tribenzyloxy-benzoic acid (585 mg, 1.32 mmol), EDC (761 mg,3.97 mmol), 1-hydroxybenzotriazole HOBt (358 mg, 2.65 mmol), DMAP (323mg, 2.65 mmol), triethylamine (461 μL, 3.31 mmol) and methylene chloride(15 mL) was stirred at room temperature under argon for 18–24 hoursafter which all starting alcohol was consumed as confirmed by TLC. Themixture was then poured into 20 mL of 2N HCl solution, extracted withethyl acetate, dried over magnesium sulfate and evaporated to dryness.The crude thus obtained was purified by flash chromatography on silicagel using 20% of ethyl acetate in hexanes to afford a white solid (650mg, 96% yield). ¹H NMR (300 MHz, CDCl₃): 2.74 (dd, J=6.6, 17.1 Hz, 1H,4-H), 2.95 (dd, J=5.7, 17.1 Hz, 1H, 4-H), 3.79 (s, 3H, OCH₃), 3.81 (s,3H, OCH₃), 4.98–5.22 (m, 13H, OCH₂Ph, 3-H), 5.38–5.44 (m, 1H, 2-H), 6.15(d, J=1.5 Hz, 8-H), 6.21 (d, J=1.5 Hz, 6-H), 6.71 (s, 2H, 2′,6′-H),7.20–7.45 (m, 32H, Ar—H, 2″,6″-H).

The hydrogenolysis of this hexabenzyloxy ester as described above forthe syntheses of Examples 1–4 gave the desired polyphenol SR 13198 in86% yield as a yellowish solid after reverse phase chromatography usinga gradient of methanol in water (from 7/3 then 1/1 then 3/7respectively). ¹H NMR (300 MHz, acetone-d₆): 2.75–2.79 (m, 2H, 4-H),3.77 (s, 3H, OCH₃), 3.78 (s, 3H, OCH₃), 5.16 (d, J=4.8 Hz, 1H), 5.40 (q,J=4.8 Hz, 1H), 6.13 (d, J=2.4 Hz, 1H, 8-H), 6.15 (d, J=2.4 Hz, 1H, 6-H),6.46 (s, 2H, 2′,6′-H), 7.03 (s, 2H, 2″,6″-H), 7.25 (s, 1H, OH), 7.84 (s,2H, OH), 7.99 (s, 1H, OH), 8.16 (s, 2H, OH). MS (ESI, negative ion mode)485 (M−1), 971 (2M−1).

EXAMPLE 6 SYNTHESIS OFcis-5,7-DIMETHOXY-2-(3,4,5-TRIHYDROXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,3,4,5-TRIHYDROXY-BENZOIC ACID ESTER (SR 13199)

The above compound, also an A-ring analog of EGCG, was synthesizedaccording to Scheme 3 (FIG. 3), as follows:

(a) Preparation of5,7-dimethoxy-2-(3,4,5-tribenzyloxyphenyl)-2H-chromen-3 (4H)-one (22):3-Flavanone 22 was prepared by the Dess-Martin periodinane oxidation of21 using the same procedure used for the synthesis of 7. The whitecrystalline 3-flavanone 22 was obtained in 80% yield after flashchromatography on silica gel using 20% of ethyl acetate in hexanes. ¹HNMR (300 MHz, CDCl₃): δ 3.43 (d, J=21.4 Hz, 1H, 4-H), 3.53 (dd, J=0.9,21.4 Hz, 1H, 4-H), 3.79 (s, 3H, OCH₃), 3.80 (s, 3H, OCH₃), 5.01 (s, 2H,OCH₂Ph), 5.04 (s, 2H, OCH₂Ph), 5.05 (s, 2H, OCH₂Ph), 5.24 (s, 1H, 2-H),6.18 (d, J=2.4 Hz, 1H, 8-H), 6.28 (d, J=2.4 Hz, 1H, 6-H), 6.67 (s, 1H,2′-H), 6.68 (s, 1H, 6′-H), 7.24–7.39 (m, 15H, Ar—H).

(b) Preparation of (2,3-cis)-5,7-dimethoxy-2-(3,4,5-tribenzyloxyphenyl)chroman-3-ol (23): A solution of 3-flavanone 22 (1.87 g, 3.10 mmol) in30 mL of tetrahydrofuran was added dropwise to a cooled (−78° C.)solution of dried (200° C. at 0.2 mmHg for 18 h) lithium bromide (1.6 g,18.4 mmol) and L-selectride® (25 mL, 25 mmol, 1M solution intetrahydrofuran). After complete addition of 22, the dry ice bath wasremoved and the mixture allowed to warm up to room temperature. Themixture was stirred at room temperature for an additional 15 hours afterwhich most of starting material was reduced as shown by TLC. Thereaction mixture was cooled in an ice bath and subjected to an oxidativework up by adding carefully, a solution of H₂O₂ (50% in water, 15–20 mL)and 20 mL of ethanol. The mixture was diluted with ethyl acetate andwater and worked up as usual. The crude material was purified by flashchromatography on silica gel using 30% of ethyl acetate in hexane togive 740 mg of colorless oil (40% yield), which crystallized uponstanding. ¹H NMR (300 MHz, CDCl₃): δ 1.77 (d, J=2.8 Hz, 1H, OH),2.78–2.90 (m, 2H, 4-H), 3.78 (s, 3H, OCH₃), 3.79 (s, 3H, OCH₃),4.20–4.22 (m, 1H, 3-H), 4.88 (s, 1H, 2-H), 5.03–5.14 (m, 6H, OCH₂Ph),6.12 (d, J=2.4 Hz, 1H, 8-H), 6.19 (d, J=2.4 Hz, 1H, 6-H), 6.82 (s, 2H,2′,6′-H), 7.24–7.44 (m, 15H, Ar—H). ¹³C NMR (CDCl₃) 27.94, 55.41, 55.49,66.42, 71.39, 75.24, 77.22, 78.52, 92.26, 93.36, 100.29, 106.20, 127.58,127.82, 127.92, 128.17, 128.17, 128.58, 133.81, 137.02, 137.85, 138.40,153.06, 155.05, 159.26, 159.73.

(c) Preparation of(2,3-Cis)-5,7-dimethoxy-2-(3,4,5-trihydroxyphenyl)-3,4-dihydro-2H-chromen-3-yl(3,4,5-dihydroxybenzoate) SR 13199: A 5 mL thick wall microwave vial wascharged with 23 (400 mg, 0.66 mmol), 3,4,5-tribenzyloxybenzoic acid (594mg, 1.35 mmol), BOP reagent (1.19 g, 2.7 mmol), DMAP (330 mg, 2.7 mmol),diisopropylethylamine (575 μL, 3.3 mmol) and 1 mL of freshly distilledDMF. The vial was sealed and heated in a single mode (MW) Smith Creator™chamber for 5 minutes at 170° C., after which all starting material wasconsumed, as shown by TLC. The mixture was diluted with ethyl acetateand 1M solution of HCl. After work up, the crude material was purifiedby flash chromatography on silica gel with 20% of ethyl acetate inhexane to yield 600 mg of hexabenzyloxy-protected SR 13199 as acolorless oil (89% yield). ¹H NMR (300 MHz, CDCl₃): δ 3.01–3.16 (m, 2H,4-H), 3.79 (s, 3H, OCH₃), 3.781 (s, 3H, OCH₃), 4.69 (d, J=11.4 Hz, 2H,),4.81 (d, J=11.4 Hz, 2H), 4.90 (s, 2H), 4.96 (s, 1H), 4.97 (s, 1H), 5.01(s, 4H), 5.04 (s, 1H), 5.62–5.64 (m, 1H), 6.16 (d, J=2.4 Hz, 1H, 8-H),6.29 (d, J=2.4 Hz, 1H, 6-H), 6.74 (s, 2H, 2′,6′-H), 7.19–7.35 (m, 32H,Ar—H, 2″,6″-H). Hydrogenolysis of the above intermediate gave SR 13199.

EXAMPLE 7 SYNTHESIS OFcis-5,7-DIMETHOXY-2-(3,4,5-TRIHYDROXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,4-METHOXY-3,5-DIMETHYL-BENZOIC ACID ESTER (SR 13200)

The above compound, an A- and D-ring analog of EGCG, was synthesizedaccording to Scheme 3 (FIG. 3), as follows:

(a) SR 13200 was synthesized by esterification of 23 with4-benzyloxy-3,5-dimethylbenzoic acid using the same procedure as for thesynthesis of SR 13199. The tetrabenzyloxy-protected ester was obtainedin 95% yield as colorless viscous oil after flash chromatography using20% ethyl acetate in hexanes. ¹H NMR (300 MHz, CDCl₃): δ 2.23 (s, 6H,CH₃), 3.01–3.09 (m, 2H, 4-H), 3.79 (s, 3H, OCH₃), 3.782 (s, 3H, OCH₃),4.59 (s, 1H), 4.60 (s, 1H), 4.82 (d, J=11.4 Hz, 2H), 4.97 (s, 2H), 4.99(d, J=11.4 Hz, 2H), 5.04 (s, 1H), 5.61–5.69 (m, 1H), 6.13 (d, J=2.4 Hz,1H)6.82 (s, 2H), 7.18–7.38 (m, 22H, Ar—H)

Hydrogenolysis of the above intermediate gave SR 13200 in 16% yield of apinkish white solid. MS (ESI, positive ion) 505 (M+Na), 986(2M+Na),1469(3M+Na). MS (ESI, negative ion) 481(M−1), 963(2M−1), 1445(3M−1).

EXAMPLE 8 SYNTHESIS OFtrans-5,7-DIMETHYL-2-(3,4,5-TRIHYDROXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,3,4,5,-TRIHYDROXY-BENZOIC ACID ESTER (SR 13911)

The above compound, an A-ring analog of EGCG, was synthesized accordingto Scheme 4 (FIG. 4), as follows:

(a) Preparation of 1-(2-Hydroxy-4,6-dimethylphenyl)ethanone (25): TiCl₄(1.2 mL, 11 mmol) was added slowly to 3,5-dimethylphenol 24 (10 mmol,1.22 g) placed in a flask flushed with argon at room temperature. Theresulting dark cherry-colored mixture was stirred at room temperature,and when gas evolution ceased, acetyl chloride (15 mmol, 1.1 mL) wasadded to the solid. The resulting thick solution was stirred at roomtemperature for 15 minutes, then brought to 120° C. and left to stir atthis temperature for an additional hour. The reaction mixture was thencooled to room temperature, diluted with methylene chloride (30 mL) andquenched with H₂O (30 mL). The organic layer was washed with H₂O (2×30mL), dried (Na₂SO₄), and concentrated under reduced pressure. The crudematerial was purified by silica gel column chromatography using amixture of 5% of ethyl acetate in hexanes to yield 1.38 g of a whitesolid (84% yield). mp 58–60° C.; ¹H NMR (CDCl₃) δ 2.27 (s, 3H, CH₃),2.56 (s, 3H, CH₃), 2.63 (s, 3H, COCH₃), 6.54 (s, 1H, Ar—H), 6.65 (s, 1H,Ar—H), 12.64 (s, 1H, OH); ¹³C NMR (CDCl₃) δ 21.77, 24.87, 33.47, 116.94,119.31, 124.70, 139.65, 146.32, 163.79, 205.64; IR (KBr, ν cm⁻¹) 2927,1622, 1353, 1216; MS (ESI) 165 (M+1). Anal. Calcd for C₁₀H₁₂O₂: C,73.15, H, 7.37. Found: C, 73.33, H, 7.37.

(b) Preparation of(2E)-1-(2-hydroxy-4,6-dimethylphenyl)-3-(3,4,5-tribenzyloxyphenyl)prop-2-en-1-one (26): The chalcone 26 was synthesized from theacetophenone 25 and benzaldehyde 12 using NaH/DMF, using the sameprocedure as for chalcone 19 (Scheme 3). The chalcone 26 was isolated asa yellow solid in 79% yield. ¹H NMR (300 MHz, CDCl₃): δ 2.30 (s, 3H,CH₃), 2.45 (s, 3H, CH₃), 5.13 (s, 2H, OCH₂Ph), 5.14 (s, 4H, OCH₂Ph),6.59 (s, 1H, 8-H), 6.67 (s, 1H, 6-H), 6.84 (s, 2H, 2′,6′-H), 7.00 (d,J=16.0 Hz, 1H, CH═CH), 7.25–7.42 (m, 15H, Ar—H), 7.55 (d, J=16.0 Hz, 1H,CH═CH), 11.24 (s, 1H, OH) ¹³C NMR (CDCl₃): δ 21.87, 23.62, 71.62, 75.55,108.67, 116.10, 120.88, 124.37, 126.61, 127.57, 128.22, 128.28, 128.46,128.79, 128.84, 130.42, 136.97, 137.71, 138.44, 141.20, 143.40, 145.50,153.31, 161.81, 196.13.

(c) Preparation of 5,7-dimethyl-2-(3,4,5-tribenzyloxyphenyl)-2H-chromene(27): To a solution of chalcone 26 (535 mg, 0.94 mmol) in a mixture oftetrahydrofuran/methanol (5 mL/20 mL) was added sodium borohydride (49mg, 1.3 mmol). The solution was brought to reflux (60–67° C.) andmaintained at this temperature for 18 hours after which all startingmaterial was consumed and a polar material was formed which was found tobe the very unstable allylic alcohol (from chalcone reduction). Thereaction mixture was cooled and the solvent was evaporated under reducedpressure. The residue was diluted with ethyl acetate and water.Evaporation of the dried organic layer yielded a viscous oil, which wassubsequently dissolved in 5 mL of ethyl acetate. To this solution, acatalytic amount of boron trifluoride etherate (10 mol %) was added atroom temperature. The mixture was left to stir overnight at the sametemperature until complete cyclization giving the desired flavene 27 in53% yield as a white solid after evaporation of solvent and flashchromatography of the crude material using methylene chloride. ¹H NMR(300 MHz, CDCl₃): δ 2.24 (s, 3H, CH₃), 2.29 (s, 3H, CH₃), 5.02 (s, 2H,OCH₂Ph), 5.08 (s, 4H, OCH₂Ph), 5.68–5.72 (m, 2H,), 6.49 (s, 1H, 8-H),6.56 (s, 1H, 6-H), 6.68 (dd, J=2.7, 11,1 Hz, 1H, 3-H), 6.77 (s, 2H,2′,6′-H), 7.28–7.41 (m, 15H, Ar—H).

(d) Preparation of(2,3-trans)-5,7-dimethyl-2-(3,4,5-tribenzyloxyphenyl)chroman-3-ol (28):The flavanol 28 was synthesized by the same hydroboration/oxidationsequence as used for 6, yielding exclusively the 2,3-trans alcohol 28 asa white solid in 95% yield after silica gel chromatography with 30% ofethyl acetate in hexanes. ¹H NMR (300 MHz, CDCl₃): δ 1.63 (d, J=3.6 Hz,1H, OH), 2.21 (s, 3H, CH₃), 2.27 (s, 3H, CH₃), 2.64 (dd, J=9.0, 16.3 Hz,1H, 4-H), 2.98 (dd, J=5.7, 16.3 Hz, 1H, 4-H), 3.95–406 (m, 1H, 3-H),4.55 (d, J=8.4 Hz, 1H, 2-H), 5.05–5.15 (m, 6H, OCH₂Ph), 6.63 (s, 1H,8-H), 6.65 (s, 1H, 6-H), 6.74 (s, 2H, 2′,6′-H), 7.24–7.44 (m, 15H,Ar—H).

(e) Preparation of SR 13911: A 5 mL thick wall microwave vial (PersonalChemistry, Inc.) was charged with 28 (400 mg, 0.7 mmol),3,4,5-tribenzyloxybenzoic acid (616 mg, 1.4 mmol), BOP reagent (1.24 g,2.8 mmol), DMAP (342 mg, 2.8 mmol), diisopropylethylamine (610 μL, 3.5mmol) and 1 mL of freshly distilled DMF. The vial was sealed and heatedin a single mode (MW) Smith Creator™ chamber for 5 minutes at 170° C.,after which all starting material was consumed as shown by TLC. Themixture was diluted with ethyl acetate and 1M solution of HCl. Afterwork up, the crude material was purified by flash chromatography onsilica gel with 20% of ethyl acetate in hexanes to yield 640 mg ofhexabenzyloxy-protected SR 13911 as a white solid (92% yield). ¹H NMR(300 MHz, CDCl₃): δ 2.18 (s, 3H, CH₃), 2.30 (s, 3H, CH₃), 2.77 (dd,J=7.0, 16.3 Hz, 1H, OH), 2.99 (dd, J=5.4, 16.3 Hz, 1H, OH), 4.97–5.20(m, 13H, OCH₂Ph, 3-H), 5.42–5.48 (m, 1H, 2-H), 6.67 (s, 1H, 8-H), 6.69(s, 1H, 6-H), 6.72 (s, 2H, 2′,6′-H), 7.18–7.46 (m, 311H, Ar—H, 2″,6″-H),

This compound was then dissolved in 1,4-dioxane and treated with 100 mgof Pd/C. The mixture was allowed to stir at room temperature under 1 atmof H₂ for 15–18 h. The suspension was then filtered, the solvent wasevaporated and the residue was chromatographed on silica gel using 10%of methanol in methylene chloride to provide 165 mg of SR 13911 as awhite solid (60% yield). ¹H NMR (300 MHz, acetone-d₆): δ 2.15 (s, 3H,CH₃), 2.24 (s, 3H, CH₃), 2.78 (dd, J=6.3, 17.1 Hz, 1H, 4-H), 2.91 (dd,J=5.4, 17.1 Hz, 1H, 4-H), 5.10 (d, J=6 Hz, 1H, 2-H), 5.43 (q, J=5.4 Hz,1H, 3-H), 6.47 (s, 2H, 2′,6′-H), 6.59 (s, 1H, 8-H), 6.60 (s, 1H, 6-H),7.03 (s, 2H, 2″,6″-H), 8.00 (br, exchangeable OHs).

EXAMPLE 9 SYNTHESIS OFcis-5,7-DIMETHYL-2-(3,4,5-TRIHYDROXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,3,4,5,-TRIHYDROXY-BENZOIC ACID ESTER (SR 13912)

The above compound, also an A-ring analog of EGCG, was synthesizedaccording to Scheme 4 (FIG. 4), as follows:

(a) Preparation of5,7-dimethyl-2-(3,4,5-tribenzyloxyphenyl)-2H-chromen-3(4H)-one (29):3-Flavanone 29 was prepared using the Dess-Martin periodinane oxidationprocedure used for the synthesis of 7. The white crystalline 3-flavanone29 was obtained in 80% yield after flash chromatography on silica gelusing 10% of ethyl acetate in hexanes. ¹H NMR (300 MHz, CDCl₃): δ 2.18(s, 3H, CH₃), 2.31 (s, 3H, CH₃), 3.43 (d, J=19.9 Hz, 1H, 4-H), 3.52 (d,J=19.9 Hz, 1H, 4-H), 5.00 (m, 6H, OCH₂Ph), 5.20 (s, 1H, 2-H), 6.69 (s,2H, 2′,6′-H), 6.74 (s, 1H, 8-H), 6.77 (s, 1H, 6-H), 7.24–7.41 (m, 15H,Ar—H). ³ C NMR (300 MHz, CDCl₃): δ 18.96, 21.33, 37.09, 71.41, 75.40,82.93, 106.47, 116.13, 116.52, 125.60, 127.71, 127.99, 128.10, 128.36,128.69, 130.73, 136.90, 137.14, 138.04, 138.22, 138.80, 153.15, 153.43,205.63.

(b) Preparation of(2,3-Cis)-5,7-dimethyl-2-(3,4,5-tribenzyloxyphenyl)chroman-3-ol (30):The cis 3-flavanol 30 was synthesized by the stereoselectiveL-selectride reduction of the 3-flavanone 29 in the same manner as givenfor 3-flavanol 23 (Scheme 3). The final product was obtained as acolorless oil (62% yield), after flash chromatography on silica gelusing 20% of ethyl acetate in hexanes. ¹H NMR (300 MHz, CDCl₃): δ 1.73(s, 1H, OH), 2.20 (s, 3H, CH₃, 2.27 (s, 3H, CH₃), 2.83 (d, J=17.1 Hz,1H, 4-H), 2.95 (dd, J=4.2, 17.1 Hz, 1H, 4-H), 4.23–4.28 (m, 1H, 3-H),4.87 (s, 1H, 2-H), 5.06 (s, 2H, OCH₂Ph), 5.13 (s, 4H, OCH₂Ph), 6.66 (s,1H, 8-H), 6.68 (s, 1H, 6-H), 6.81 (s, 2H, 2′,6′-H), 7.25–7.43 (m, 15H,Ar—H). MS (ESI, positive ion) 595 (M+Na), 1167 (2M+Na).

(c) Preparation of SR 13912: SR 13912 was synthesized using exactly thesame procedure as described in Example 8 for SR 13911. Thehexabenzyloxy-protected SR 13912 was obtained in 57% yield as colorlessviscous oil after flash chromatography using 20% ethyl acetate inhexanes. ¹H NMR (300 MHz, CDCl₃): δ 2.21 (s 3H, CH₃), 2.31 (s, 3H, CH₃),2.93 (d, J=17.7 Hz, 1H, 4-H), 3.15 (dd, J=4.5, 17.7 Hz, 1H, 4-H), 4.71(d, J=11.4 Hz, 2H), 4.83 (d, J=11.4 Hz, 2H), 4.91 (s, 2H), 4.96 (s, 1H),4.97 (s, 1H), 5.01 (s, 4H), 5.03 (s, 1H), 5.58–5.78 (m, 1H, 2-H), 6.70(s, 1H), 6.75 (s, 2H), 6.79 (s, 1H), 7.19–7.34 (m, 32H, Ar—H).

Hydrogenolysis of this intermediate, as described above, provided thedesired SR 13912 as a white solid in 53% yield. ¹H NMR (300 MHz,acetone-d₆): δ 2.15 (s 3H, CH₃), 2.24 (s 3H, CH₃), 2.78 (d, J=17.8 Hz,1H, 4-H), 3.17 (dd, J=5.1, 17.8 Hz, 1H, 4-H), 5.60–5.63 (m, 1H, 2-H),6.60 (s, 1H, 8-H), 6.61 (s, 1H, 6-H), 6.63 (s, 2H, 2′,6′-H), 7.00 (s,2H, 2″,6″-H), 7.20 (br, exchangeable OH), 7.70 (br, exchangeable OH),8.19 (br, exchangeable OH).

EXAMPLE 10 SYNTHESIS OFcis-5,7-DIMETHYL-2-(3,4,5-TRIHYDROXY-PHENYL)-3,4-DIHYDRO-2H-CHROMAN-3-YL,4-HYDROXY-3,5-DIMETHYL-BENZOIC ACID ESTER (SR 13913)

The above compound, an A- and D-ring analog of EGCG, was synthesizedaccording to Scheme 4 (FIG. 4), using exactly the same procedure asdescribed in Example 8 for SR 13911. The tetrabenzyloxy-protected SR13913 was obtained in 83% yield as colorless viscous oil after flashchromatography using 20% ethyl acetate in hexanes. ¹H NMR (300 MHz,CDCl₃): δ 2.21 (s 3H, CH₃), 2.22 (s, 6H, CH₃), 2.31 (s 3H, CH₃), 2.97(d, J=17.4, 1H, 4-H), 3.15 (dd, J=4.8, 17.4 Hz, 1H, 4-H), 4.60 (s, 1H),4.62 (s, 1H), 4.83 (d, J=11.7 Hz, 2H), 4.93 (s, 1H), 4.98 (s, 1H), 4.99(d, J=11.7 Hz, 2H), 5.04 (s, 1H, 2-H), 5.48–5.78 (m, 1H, 3-H), 6.67 (s,1H), 6.76 (s, 1H), 6.83 (s, 2H), 7.18–7.67 (m, 22H, Ar—H).

Hydrogenolysis of this intermediate gave the desired SR 13913 as a whitesolid in 60% yield. ¹H NMR (300 MHz, acetone-d₆): δ 2.15 (s 3H, CH₃),2.20 (s, 6H, CH₃), 2.24 (s 3H, CH₃), 2.90 (d, J=17.4 Hz, 1H, 4-H), 3.17(dd, J=4.8, 17.4 Hz, 1H, 4-H), 5.10 (s, 1H), 4.00–4.05 (m, 1H, 3-H),4.05 (s, 1H, 2-H), 5.09 (s, 1H), 5.10 (s, 2H), 5.96 (s, 2H), 6.11–6.42(br, exchangeable OH).

EXAMPLE 11 In Vitro Determination of Growth Inhibitory Activity

Compounds of the invention were tested for their ability to inhibitgrowth in two breast cancer cell lines, MCF-7 (ER+) and MDA-MB-231(ER−).

The growth inhibition assays were conducted using routine methods.Briefly, the cells were seeded in 24-well plates at a density of 2000cells per well in 200 μL of water containing growth medium. To each wellwas added 10 μL of DMSO containing the dissolved test compound; finalDMSO concentration in each well was not more than 0.5%. Each testcompound was assayed at concentrations of 0.4, 2, 10, and 50 μM. Theplates were incubated for eight days, with the media and test solutionsreplaced every third day. On Day 8, the viable cells were measured bythe MTT assay, as described in Mosmann et al. (1983), “RapidColorimetric Assay for Cellular Growth and Survival: Application toProliferation and Cytotoxicity,” J. Immunol. Method. 65:55–63. Theoptical density at 575 nm of each test well was measured and compared tothat for control wells, and the data used to calculate the percentage ofgrowth inhibition at different concentrations. The IC₅₀ value (theconcentration of growth inhibitor that results in 50% growth inhibitionof the cells in culture relative to control cells not exposed to anygrowth inhibitor) was determined by plotting dose-response curves.

The calculated IC₅₀ values are set forth in Table 1, with the resultsrepresenting the average of at least two experiments conducted for eachcompound at each of the four concentrations. As may be seen, a number ofthe experimental compounds demonstrated growth inhibitory activityagainst both of the breast cancer cell lines.

TABLE 1 Growth Inhibition (IC₅₀) (μM) Compound MCF-7 (ER+) MDA-MB-231(ER−) SR 13194 >100 >100 SR 13195 >100 >100 SR 13196 11.05 12.66 EGCG(2,3-cis) 8.22 11.94 EGC (2,3-cis) 29.75 27.26

The foregoing procedures were repeated with additional compounds of theinvention to evaluate the their ability to inhibit growth in MCF-7 (ER+)and MDA-MB-231 (ER−). The results obtained are set forth in Table 2:

TABLE 2 Growth Inhibition (IC₅₀) (μM) Compound MCF-7 (ER+) MDA-MB-231(ER−) SR 13911 23.51 42.02 SR 13912 39.56 62.09 SR 13913 16.17 20.11 SR13197 123.96 55.36 SR 13198 58.06 47.94 EGCG 16.807 5.76

EXAMPLE 12 In Vitro Determination of Growth Inhibitory Activity

An anchorage-independent growth inhibition assay was performed asdescribed in Korytynski, et al. (1996) “The development of ananchorage-independence assay using human lung tumor cells to screenpotential chemopreventive agents,” Anticancer Res. 16, 1091–1094; andSharma, et al. (1997) “The anchorage-independent assay as a screeningtool to identify potential chemopreventive agents,” Methods Cell Sci.19, 9–12. The assay measures the inhibition of colony formation of humanlung tumor cells (A427) cells grown in soft agar. In this assay, A427cells were grown in the presence of the test agent, SR 13196, EGCG or13-cis-RA Control samples were tested using an equivalent volume of DMSOalone. A concurrent assay for cell survival was also performed.

As can be seen from the data presented in the table below, SR 13196inhibited colony formation to a much greater extent than either EGCG or13-cis-RA At the highest concentration of SR 13196 tested (25 μM), 81%inhibition of the growth of the tumor cells was observed. In comparison,at the same concentration, EGCG and 13-cis-RA only inhibited 50% and 43%respectively. Similarly, at the highest concentration tested, SR 13196showed only 11% surviving cells, in comparison with 39 and 68% for EGCGand 13-cis-RA respectively. Thus, SR 13196 inhibits colony formation ofA427 cells in vitro, as well as their survival, and in a dose-dependentmanner.

TABLE 3 Com- Surviving Observed Expected pound Dose (μM) FractionColonies Colonies % Inhibition DMSO — 1.0 390 390 — Control SR 13196 250.11 8 43 81 12.5 0.12 28 52 46 6.25 0.17 38 67 43 3.12 0.41 108 160 321.56 0.71 268 277 4 EGCG 25 0.39 97 191 50 12.5 0.85 139 331 40 6.250.97 282 378 25 3.12 0.98 310 382 19 1.56 0.99 398 386 0 13-cis-RA 250.68 142 254 43 12.5 0.74 179 265 35 6.25 0.83 206 289 28 3.12 0.82 269320 16 1.56 0.85 310 332 8

1. A compound having the structural formula (I)

wherein: R¹, R² and R³ are independently selected from the groupconsisting of hydroxyl, halo, sulfhydryl, alkoxy, aryloxy, andaralkyloxy; R⁴ is O; R⁵ is selected from the group consisting of SH,acyloxy, and N(R^(x))₂ wherein the R^(x) may be the same or differentand are hydrogen or alkyl; R⁶ and R⁸ are independently selected from thegroup consisting of alkyl, alkoxy, aryloxy, and aralkyloxy; R⁷ and R⁹are independently selected from the group consisting of hydrogen, alkyl,alkoxy, aryloxy, and aralkyloxy; and R¹⁰ and R¹¹ are independentlyselected from the group consisting of hydrogen, hydroxyl, alkyl, alkoxy,and halo, with the proviso that when (a) R⁷, R⁹, R¹⁰, and R¹¹ arehydrogen, (b) R¹, R², R³, R⁶, and R⁸ are hydroxyl, and (c) R⁴ is O, then(d) R⁵ is other than 3,4,5-trihydroxybenzoyloxy or3,4,5-trimethoxybenzoyloxy.
 2. The compound of claim 1, wherein R¹, R²and R³ are independently selected from the group consisting of hydroxyl,halo, C₁–C₆ alkoxy, C₅–C₁₂ aryloxy, and C₅–C₁₂ aralkyloxy; R⁵ isselected from the group consisting of C₆–C₃₂ acyloxy, and NH₂; R⁶ and R⁸are independently selected from the group consisting of C₁–C₆ alkyl,C₁–C₆ alkoxy, C₅–C₁₂ aryloxy, and C₅–C₁₂ aralkyloxy; R⁷ and R⁹ areindependently selected from the group consisting of hydrogen, C₁–C₆alkyl, C₁–C₆ alkoxy, C₅–C₁₂ aryloxy, and C₅–C₁₂ aralkyloxy; and R¹⁰ andR¹¹ are independently selected from the group consisting of hydrogen,hydroxyl, C₁–C₆ alkyl, C₁–C₆ alkoxy, and halo.
 3. The compound of claim2, wherein R¹⁰ and R¹¹ are hydrogen.
 4. The compound of claim 3, inenantiomerically pure form in the 2β,3β-cis, 2α,3α-cis, 2α,3β-trans, or2β,3α-trans configuration.
 5. The compound of claim 3, comprising aracemic mixture of the 2α,3β-trans and 2β,3α-trans enantiomers.
 6. Thecompound of claim 3, comprising a racemic mixture of the 2α,3α-cis and2β,3β-cis enantiomers.
 7. The compound of claim 3, wherein: R¹, R² andR³ are identical, and are selected from the group consisting of C₁–C₆alkoxy and C₅–C₁₂ aralkyloxy; R⁵ is an acyloxy substituent having thestructure

in which R¹², R¹³, and R¹⁴ are independently selected from the groupconsisting of hydroxyl, C₁–C₆ alkyl, C₁–C₆ alkoxy, and C₅–C₁₂aralkyloxy; and R⁶ and R⁸ are C₁–C₆ alkyl, C₁–C₆ alkoxy, or C₅–C₁₂aralkyloxy and R⁷ and R⁹ are hydrogen.
 8. The compound of claim 7,wherein: R¹, R² and R³ are selected from the group consisting of methoxyand benzyloxy; and R⁵ is an acyloxy substituent having the structure

in which R¹², R¹³, and R¹⁴ are independently selected from the groupconsisting of hydroxyl, methyl, methoxy, and benzyloxy.
 9. Apharmaceutical composition comprising a therapeutically effective amountof the compound of claim 1 in combination with a pharmaceuticallyacceptable carrier.
 10. A pharmaceutical composition comprising atherapeutically effective amount of the compound of claim 2 incombination with a pharmaceutically acceptable carrier.
 11. Apharmaceutical composition comprising a therapeutically effective amountof the compound of claim 3 in combination with a pharmaceuticallyacceptable carrier.
 12. A pharmaceutical composition comprising atherapeutically effective amount of the compound of claim 4 incombination with a pharmaceutically acceptable carrier.
 13. Apharmaceutical composition comprising a therapeutically effective amountof the compound of claim 5 in combination with a pharmaceuticallyacceptable carrier.
 14. A pharmaceutical composition comprising atherapeutically effective amount of the compound of claim 7 incombination with a pharmaceutically acceptable carrier.
 15. Apharmaceutical composition comprising a therapeutically effective amountof the compound of claim 8 in combination with a pharmaceuticallyacceptable carrier.
 16. The composition of any one of claims 9 through15, wherein the pharmaceutically acceptable carrier is suitable for oraladministration and the composition comprises an oral dosage form. 17.The composition of claim 16, wherein the oral dosage form is a tablet.18. The composition of claim 16, wherein the oral dosage form is acapsule.
 19. The composition of any one of claims 9 through 15, whereinthe pharmaceutically acceptable carrier is suitable for parenteraladministration and the composition comprises a parenterallyadministrable formulation.